Citation
Reactivity in the tricyclo 4.1.0.02 4 heptan-5-ylidene and the tricyclo 5.1.0.03 5 octan-2-ylidene series

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Title:
Reactivity in the tricyclo 4.1.0.02 4 heptan-5-ylidene and the tricyclo 5.1.0.03 5 octan-2-ylidene series
Added title page title:
Tricyclo 4.1.0.02 4 heptan-5-ylidene and the tricyclo 5.1.0.03 5 octan-2-ylidene series, Reactivity in the
Added title page title:
Tricyclo 5.1.0.03 5 octan-2-ylidene series, Reactivity in the tricyclo 4.1.0.02 4 heptan-5-ylidene and the
Creator:
Garza, Oscar Trinidad, 1947-
Copyright Date:
1975
Language:
English
Physical Description:
x, 176 leaves : ill. ; 28cm.

Subjects

Subjects / Keywords:
Absorption spectra ( jstor )
Carbenes ( jstor )
Fine structure ( jstor )
Hydrazones ( jstor )
Isomers ( jstor )
Mass spectroscopy ( jstor )
Pyrolysis ( jstor )
Reaction mechanisms ( jstor )
Sodium ( jstor )
Spectral methods ( jstor )
Chemistry thesis Ph. D
Corbenes ( lcsh )
Dissertations, Academic -- Chemistry -- UF
City of Jacksonville ( local )
Genre:
bibliography ( marcgt )
non-fiction ( marcgt )

Notes

Thesis:
Thesis--University of Florida.
Bibliography:
Bibliography: leaves 171-175.
General Note:
Typescript.
General Note:
Vita.
Statement of Responsibility:
by Oscar Trinidad Garza.

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University of Florida
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University of Florida
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Copyright [name of dissertation author]. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
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02707498 ( OCLC )
AAS8825 ( NOTIS )

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ACTIVITY IN THE TRICYCLO [4.1.0.02'4] HEPTAN-5-YLIDENE
ND THE TRICYCLO [5.1.0.03'5] OCTAN-2-YLIDENE SERIES


4.


OSCAR TRINIDAD GARZA


iSENTED TO THE GRADUATE COUNCIL
UNIVERSITY OF FLORIDA
MENT OF THE REQUIREMENTS F@R TH
F DOCTOR OF PHILOSOPHY


FLORID


















To Mawy Jane








(










NOWLEDGEMENTS


author wishes to express his deepest grati-

WtR. Dolbier, for the patience, encour-

d dance which were afforded the author

years of doctoral research. Without Dr. Dolbier's

and suggestions, this work would not have

i she d

auth *shes to express his appreciation to

s of pervisory committee, in particular

research accomplished with the

gro'up. Further gratitude is ex-

r his invaluable varied services

arch goals on many occasions.

ially owed to Pat and

ng~h tim d, did

copies


ar uthor'







TABLE OF CONTENTS


Page

ACKNOWLEDGEMENTS ................................... iii
LIST OF TABLES ................... ................. v
LIST OF FIGURES .................... ............... vi
ABSTRACT ...................... ................... ix

CHAPTERS:
I. INTRODUCT ION ............. .................. 1
II. SYNTHETIC METHODS ........................... 13
III. PYROLYSIS OF p-TOLUENESULFONYLHYDRAZONE
SODIUM SALTS .............................. 39
IV. DISCUSSION AND CONCLUSIONS .................. 59
V. EXPERIMENTAL ........... ...................... 88

APPENDIX .................. ............. ............ 138
REFERENCES ......................................... 17
BIOGRAPHICAL SKETCH ................................ 176


L' 'v
/ 1
^^Aij













LIST OF TABLES
Page


26-s + Eu(fod)3. 100

26-a + Eu(fod)3. 100

Proton Assignments for 26-s and 26-a in
the 100 MHz Spectra. 101

Reaction Product Yields from syn-Tricyclo
[4.1.0.02,4] heptan-5-one Tosylhydrazone
Sodium Salt. 119

Reaction Product Yields from Flow Pyroly-
sis of syn-Tricyclo [4.1.0.02,4] heptan-
5-one Tosylhydrazone Sodium Salt. 121

Reaction Product Yields from anti-Tricyclo
[4.1.0.02,4] heptan-5-one Tosylhydrazone
odium Salt. 122

Reaction Product Yields from syn- and
nti-Tricyclb [5.1.0.03,5] octan-2-one
sylhydrazone Sodium Salts. 123
latile Product Yields from Static Py-
lysis of syn- and anti-Tricyclo
.1.0.02,4] heptan-5-one Tosylhydrazone
dium Salts: 1400-2250. 137












v


I i A










LIST OF FIGURES


Figure Page

1 'H 60 MHz nmr of syn-tricyclo [4.1.02,4]
heptan-5-one (26-s). 29
2 Nmr of Eu(fod)3 / 26-s: Molar ratio, 0.13. 30

3 Nmr of Eu(fod)3 / 26-s: Molar ratio, 0.25. 31

4 Nmr of Eu(fod)3 / 26-s: Molar ratio, 0.38. 32

5 Nmr of Eu(fod)3 / 26-s: Molar ratio, 0.50. 33

6 60 MHz nmr of anti-tricyclo [4.1.0.02,4]
heptan-5-one (26-a).

7 Nmr of Eu(fod)3 / 26-a: Molar ratio, 0.10.

8 Nmr of Eu(fod)3 / 26-a: Molar ratio, 0.20.

9 Nmr of Eu(fod)3 / 26-a: Molar ratio, 0.30.

10 Nmr of Eu(fod)3 / 26.f : Molar ratio, 0.40.

11 Hilh-vacuum pyrolysis system.

A-i 'H 100 Mhz nmr of syn-tricyclo [4.1 .02,4
heptan-0-one (26-s).
A-2 100 MHz nmr of anti-tri yclo [4.1 2,
heptan-5-one (26-a).

A-3 Nmr of syn -Iicyclo [5.1.0.03
one (49 -s)w

A-4 Nmr anti-
one -a).

A-5 Nmr of -tri
0 d one t









F Page
Nmr of anti-tricyclo [5.1.0.03,5] octan-
2-one tos hlhydrazone (50-a). 146

Nmr of dimer 52 obtained from 33-a sodium
salt. 147
)mr of dimer 52 obtained from 33-s sodium
alt. 148

Nmr of 4-ethynyl-cyclopentene (55). 149

100 MHz nmr of trans-1-ethynyl-2-vinyl cy-
clopropane (54-t). 150

00 MHz nmr of cis-l-ethynyl-2-vinyl-
clopropane (54-c). 151

0 MHz nmr of cyclopropyl region of 54-c. 152

of cis-l-allyl-2-ethynyl-cyclopropane
). 153

cf octa-l,2,5,7-tetraene (66). 154

o n-tric clq [4.1.0.02, 4] heptan-5-
6-s) 24155

yclo [4.1.0.02,4] heptan-5-
156

yclo [5.1.0.03,5] octan-2-
157

cyc [5.1.0.03,5] octan-2-
158

.1.0.02,4] heptan-5-
s). 159

.0.02'4] heptan-5-
-a).160
5] octan-2-one
161

,5 octan-2-
S .162







Figure Page *
A-25 Ir of dimer 52 from 33-s sodium salt. 163
A-26 Ir of dimer 52 from 33-a sodium salt. 164
A-27 Ir of dimer 52 from cis-l-ethynyl-2-vinyl
cyclopropane (54-c). 165
A-28 Ir of trans-l-ethynyl-2-vinyl-cyclopropane
(54-t). 166
A-29 Ir of cis-1-ethynyl-2-vinyl-cyclopropane
(54-c). 167
A-30 Ir of 4-ethynyl-cyclopentene (55). 168
A-31 Ir of cis-1-allyl-2-vinyl-cyclopropane (65). 169
A-32 Ir of octa-1,2,5,7-tetraene (66). 170















v( i






A vii i








Wf Dissertation Presented to the Graduate Council
versity of Florida in Partial Fulfillment of the
events for the Degree of Doctor of Philosophy

IVITY IN THE TRICYCLO [4.1.0.02,4] HEPTAN-5-YLIDENE
THE TRICYCLO [5.1.0.03,5] OCTAN-2-YLIDENE SERIES


By
Oscar Trinidad Garza

August, 1975

William R. Dolbier, Jr.
artment: Chemistry

e thermal conversions of the p-toluenesulfonylhy-

ium salts of (a) the syn-and anti-tricyclo

] heptan-5-ones as well as those of (b) the syn-
icyclo [5.1.0.03,5] octan-2-ones were investi-

try resulting from the generation and sub-
o W f the respective carbenes for each series
-for ty casr of the tricyclic hep-


wer-loeveloped for the required syn-

nti-tricyclo [4.1.0.02,4] heptan-5-
affording nearly equimolar mix-

tone while the third method af-
ure i e ratio 2:98. The novel
gly labile in








Carbene product distributions for both isomers in

a given series proved similar thereby demonstrating that the

cyclopropane orientation differences within an isomeric set

afforded no readily identifiable differences in reactivity.

Although the observed products for each series studied

could be explained largely by the established ethylenic-

acetylenic fragmentation process common to cyclopropyl car-

benes, the case for the isomeric tricyclic heptanylidenes

was subjected to further scrutiny because of the plausible

operation of a novel six-electron pericyclic process in-

volving the highly-strained species 1,2,5-cycloheptatriene

as the primary product derived from either tricyclic hep-

tanylidene.

Three C7H8 monomers and one C7H8 dimer were obtained

from the tricyclic heptanylidenes while two C8H10 monomer

were isolated from the tricyclic octanylidenes. The novel

C7H8 monomer cis-l-ethynyl-2-vinyl cyclopropane afforded

unusual reactivity, undergoing ostensibly a Cope rearra

ment with an approximate half-life, assuming a unimolecu

rate-determining step, of two to three hours max

250C. It remains the subject of ongoing studies

proved to be the most interesting carbene produ

from the studies of both tricyclic carbene sys













CHAPTER I

INTRODUCTION AND BACKGROUND



The question of a quasiaromatic structure as a

picturee of the electronic makeup of certain suitably-

id carbenes has received considerable attention in

;t decade.1 Although cyclopropenylidene (1) has

dy thus far, cyclopentadienylidene (2) and cyclo-

ylidene (3) have been studied in detail.1,2









03



s 4 aAd 5 to 2 and 3, re-

bstantial experimental verifica-
3,4
k by two research groups34 sup-
el calculations performed by














4 (p2) 5 ( 2)



The EHT calculations indicate that the nucleophilic or

electrophilic character ought to alternate in the series

1 3. The nucleophilic character of 1 and 3, with the
2 2
a2 singlet of each lower than the p singlet on the poten-

tial energy profile, was predicted from calculations of

the total charge residing on the respective methylene car-

bons of 1 and 3: -0.68 and -0.86. Experimental evidence
was in turn provided by W.M. Jones and coworkers in the

case of 3. A Hammett study was performed in which cycle
heptatrienylidene was generated in the presence of an
eight-to-teftkold excess of an equimolar mixture styr

and 3- or 4-substitutid styrenei he p value .05
0.05 obtain d from tit study pr vided the first anti
tative asse ment of e nucleoph city of a

aromati carbene.

lopentadie ne, on
readily lend itself o

it jae o e x

d a










CH3


+ :C*


8



imattc carbene. In the case of 6 the vigorous

resultingg in extrusion of carbon atoms may pre-

existence of a bishomoaromatic carbene (9).

immett studies and suitable trapping reactions

Roth electron-rich and electron-poor olefins,

Lt afford information concerning the









electrophilicity or nucleophilicity of 6 and 7, no evidence

for bishomoaromaticity in 6 and 7 would appear to be forth-

coming. Even the isolation of stable forms, dimers and/o 9

oligomers, of 10 and 11, derived from 6 and 7, respectively,

while perhaps suggesting a special intermediate as their

precursor, would not demonstrate bishomoaromaticity as an

operative force in these systems.














10 11





The discussion of bilhomoromati

of 7, fortunately, can be extended du
work performed y Bergman and Rajadhyak

the same pap Treatment of 3-br

* octa-2,6-di 0 ota

.^ 250 afford%









rate determining step of the reaction, and (b) rapid, re-
versible deprotonation-reprotonation of 12 occurred at a
rate greater than that of rearrangement. The scheme postu-
lated by Bergman envisioned a homoconjugated anion (13)



t-Buo
Br 0Br
t-BuOH

12 13






S+ Br


14



y o a homoconjugated neutral intermediate (14)
equently underwent cleavage in the manner typi-
propylcarbenes. Since 7 and 13 both afforded
d t (@, it was logical that a common inter-
ould be invoke, the final result being
ep nation (15) which corresponds to
atio the singlet carbene. In summary





O *A6m









it can be stated that the isolation of 8 via generation of

7 from the tosylhydrazone sodium salt does not appear to be


15(p2)


merely a simple case ofacyclopropylcarbene undergoing th

well-documented ethylene-acetylene fragmentation process

but is, in fact, a case of a stabilized carbene givin

product (8). Alt ugh further argument concern ing t

mechanistic ii ff 8 may prove ethereal, it is

able that 8 cou arise from all&ne (11) b

process.11









S Consideration of the 1,3-bishomocyclopentadienide

ecies (16), of which 15 would be the a cation, allows

rather insight into the postulated existence of 15. HMO

culations predict appreciable bonding interactions be-

the allylic anionic and olefinic systems in 16.1

sonance integral B27 (or B46) is approximately equal

0B where 0 is assigned a value of 18 kcal/mole,
normally used for benzenoid systems.3 Charge




5



3



17 18




st at C-2 and C-4 (0.426), considerably
C-7 (0.064), and least at C-3 (0.021).

y enough, the tetracyclic hydrocarbon (18)
ne n' ree products upon equilibration

user's catalyst-solvent system,


er test the hypothesis of bishomo-
bene chemistry, it was




110



deemed necessary to investigate this question from the
viewpoint of bishomocyclopentadienylidene, a species
which could possess two isomeric forms; i.e., syn and
anti configurations of the fused cyclopropane rings should
be possible. The bishomocyclopentadienylidenes, syn- and
anti-tricyclo [4.1.0.02,4] heptan-5-ylidenes, 19-s and
19-a devoid of the molecular constraints as encountered in







19-s 19-a


6 and 7, would be capable of generating the novel cyclic
allene 1,2,5-cycloheptatriene (20), whosf structural de-
formation would place it in the same class with the known
1,2-cycloheptadiene (21) and 1,2-cyclohexadiene (22) s
cies. 14ab Monomers 21 and 22 have been sh n to be




L I *




911




intermediates as evidenced by the isolation of

dimeric and tetrameric products. In the case of 22
OM l o been ,trapped employing both styrene

,3-dipheny rbenzo [c]-furan.5ab The observation of
ssible d @r and/or tetrameric products resulting from

Vould lend credence to the concept of a bishomoaromatic
e4 49thiah bch an observation, by itself, constitutes

ique multiple-bond fragmentation process for a new car-

ather than the actual generation of a particular

stabilized carbene.

their int sting features of the bishomocyclo-

igation would lie in the isolation
cis-1-ethynyl-2-vinyl-cyclopro-

[4.1.0.02'403,5] heptane (24).
ts an interesting problem
e from 20 via a Cope process

ry product from the ethy-
ocess common to cyclopropyl-
echanistic alternatives

inherent stability and reac-
tracyclic heptane (24), syn-

and Bri.ntrup,16 converted

a reaction halflife of
of approximately #




V


suggesting that suitably-generated 19-s or 19-a might give
rise to 24 via C-H insertion.


23 (=54c)
r


Further speculation about the reactivity of 19-s
and 19-a only served to increase the demand for the actual
experimental work. The work described in this disser
was performed principally on the syn-and anti-tricyc
[4.1.0.02,4] heptan-5-ylidenes in order to determi
basic reactivity of these systems and thereby add
discussion of homoaromaticity in alicyclic carbe
their elaboratTon of the working hypothesis was
by inspection of the syn-and anti-tricy
octanA2JylidenIs, 28 a and 9 h
test for operational homoaromhti r y
possessing favorable ge entries.


LI


4~


1% 1


4














P CHAPTER II

4A SYNTHETIC METHODS


SSnthe try into both the tricyclo [4.1.0.02,4]
an-5- lidene and the tricyclo [5.1.0.03,5] octan-2-

ne ser w s I'rovided by the synthesis of the corre-

nding syWnd ti ketones for each series. Conversion

the ketonel to the corresponding p-toluenesulfonylhydra-

)hydrazones) was desirous since tosylhydrazone
iunPor potassium salts are normally stable pre-
ch can be subsequently pyrolyzed or photolyzed
1,2or pyrolyzed in the solid state a la Schecter.17

synthetic methods were developed for the syn-
ti-tricyclo [4.1.0.02,4] heptan-5-ones,
ly. The first two methods (methods
farly even mixture of the syn
third method (method C) afforded
ratio of 2:98.

I) began with the known conversion
responding acid chloride fol-

mine to afford the dimethyl-
obutanedione (27).18

ner,19 with allyl Grignard









afforded the C14 keto-alcohol, 5-allyl-5-hydroxy-2,4,4-
trimethyl-7-octen-3-one (28), which was subsequently con-
verted to diallyl ketone (29) by base-catalyzed cleavage
with barium hydroxide.19 Diallyl ketone (29) was converted
to its ethylene ketal (30) which was treated with iodoben-
zene dichloride. 20ab The crude mixture of cis-and trans-

7,8-bis (chloromethyl)-1,4-dioxaspiro [4.4] nonanes (31),
the product of addition of one mole of chlorine concomitant I
with radical cyclization to generate the five-membered carbo-
cyclic structure, was subjected to acid-catalyzed hydroly-
sis resulting in restoration of the ketone moiety. The
resulting mixture of cis-and trans-3,4-bis (chloromethyl)-
cyclopentanones (32) was treated with 50% sodium hydroxide
whereby an a, loss of two moles of HC1 was effected re-
sulting in the isolation of two ketonic products which nm
ir, uv, mass spectral, and elemental analyses indicated to
be C7H80 isomers.
The isolation of the two ketonic products, which
proved to be the desired tricyclic heptanones, 26-s an
26-a, proved initially troublesome when attempt'
separation work employing typical glpc methods. An
tion of the isomeric mixture of ketones onto various ar
wax 20 M columns (column temperatures: 130C-1600C
ically resulted in the isolation of t e some
(a) anti-tricyclo [4.1.0. 4] hetan-5-o

cyclohen and (c) -cy heptadie
&^^B& 211 ^^^^^^













SOC12 NEt3
----h--t --s-


0



27
__^


1) CH = CH-CH MgBr

2) NH4C1


Ba(OH)2


CH2C1


CH2C1


Cm (fP3


H

H20, EtOH


4 1 0


syn:anti
52:48


n I


6'
4.







Scheme I continued


26-a




N-NI -Tos


26-s




N-NH-Tos


33-a





I


33-s


Na
Tos -N -N =



34-a
ft


Na
N N Tos


34-s
ri


Il


I








icyclic ketone was identified by comparison of its

0 MHz) with that reported by Gajewski and Shih
.21 The outstanding feature of the nmr of 26-a is

Symmetrical quartet (J = 3.5 Hz) with a two-proton
ation at 6 0.85. The remainder of the nmr spectrum
d three multiplets of two-proton integration each
at 6 1.25, 1.56, and 2.08. The ir (1720 cm-1),

ax 287 nm, E 28), and mass spectrum (M+ 108) were
confirmative of the anti isomer; however, elemental
s id not prove satisfactory, a situation which
until pc method were rectified.
The 2,4 a 3,5-cyclcheptadienones, recognizable
e fo 'otPn multiple in the region 6 2.17-

ee r and (b)the four-proton doublet
entered at 6 3.00 for the 3,5 isomer,22 were

ca--promoted rearrangement which de-
ction of the syn-trifyclic ketone
rtion of the anti PIction (26-a).
Borg and Kloosterzil had shown that the
terconvertible in the temperature
1,5 hydrogen shift, resulting
dominated by the 2,4 isomer.22
d th rvation that the cyclo-

h~ g umn as a mixture
26-a elu d as a
0


HP




"


0 0 0

HO








Isolation of analytically pure syn-and anti-tric
heptanones was accomplished by the use of an alkaline co
umn (10% Carbowax 20 M) employing 3.5% potassium hydroxid
to effectively remove active sites from the inert support
typically Chromasorb P-Regular. Whereas liberal inje ns
of ammonia vapor had not prevented destructiogfo
tones in the initial glpc work, the potassium hydroxi
coated column allowed for almost quantitati
* cyslohept nofR as iltiernal standard) se ion
lion Of 26-s anti in tht temphr-atur rng 30
It" rt &td t 4 W1.itkt column tSmo t
range k850-19 0 led gain to the a t complete
f 4 (4% recovery) s-s esli t
some s y le.
T~he novel y.1 2
forde fout com
1 ti








The multiplets at 1.50 and 1.78 were overlapping, a featui'

whi readily distinguishes 26-s from 26-a. The ir (1700

uv (Xmax 283, c 70), and mass spectrum (M+ 108) also
firmed the structure of this C7H80 ketone isomer. Ele-

tal analysis of 26-s proved satisfactory.

Silica gel chromatography conveniently afforded

paration of 26-s and 26-a of sufficient purity to allow

r subsequent conversion to the corresponding tosylhydra-

nes, 33-s and 33-a, respectively. Whereas 33-s was ob-

erved to have been formed in 83% yield, 33-a, unfortunately,

as obtained in only 31% yield. Conversion of 33-s and

33-a to the corresponding sodium salts, 34-s and 34-a, was

anti ively achieved employing sodium hydride (1.2

nts) with tetrahydrofuran solvent. Potassium salts

and 33-a were made by treatment of the tosylhydra-

otassium tert-butoxide, again using tetrahydro-

t.

od B (ScIeme II) employed a synthetic sequence

ed to bt'a mort convenient synthetic route than

Drawing on the analogy provided by workers such

d Gutsche24 in performing intramolecular

ediates of the copper-ketocarbene type

e bond, a sequence of steps was devised

ii ze cis-ethyl-2-vinyl-cyclopropanecarboxy-

he point of entry into the synthetic se-
no stereospecific synthesis of 35-c has








Scheme II


+ N2CHCO2Et


KOH
H20---MeOH
H O-MeOH
2


CuSO
MEN 0


C-C
II


1100
--^


CO Et t
35 9
%


SOC12
------


CH2N2


C-C1
I I


lo




S21




e reported to date, a cc. venient synthesis of cis-and

trans-ethyl-2-vinyl-cyclopropanecarboxylates (35) was

supplied by Vogel and coworkers.25 The cis-trans ratio of
5was determined to be 40:60. Saponification of cis-and

trans-35 afforded the corresponding mixture of cis-and

trans-cyclopropanecarboxylic acids (36). Treatment of 36

with thionyl chloride afforded a 38:62 mixture of the cis-

nd trans-cyclopropanecarbonyl chlorides (37). Up to this

int the synthetic work was essentially a duplication of

gel's work which had been concerned with the synthesis

d reactivity cis-and trans-2-vinyl-cyclopropylisocya-
25
atel Treatment of 37 with ethereal diazomethane af-

a c'ude mixture of cis- and trans-l-diazomethylketo-
-c loflopanes (38) as evidenced by the strong ir
a-1
-1 ad the diazomethyl singlet at 6 5.31

nmr. pper-catalyzed.decomposition of 38 in re-
0 *
exane afforded the desired isomeric tricyclic
nd 26-a, in the syn-anti ratio of 47:53;
ed upon the cia acid chloride (37).

ot providing a satisfactory syn-
id pr ide an interesting route to 26-a.
r the synthetic sequence, as outlined

clo [3.1.0] hexan-2-one (39)

ly synthesized from either 4-
yclopentenone.27







Scheme III


I 0


Br
(CH2OH)2
S2


NaOMe
DMSO


0


L


3% H2SO4
---,-,


G0
(CH3 3SO I

NaH
DMSO


26-a


syn :anti
2:98


Initially employing the basic procedure for the
synthesis of bicycle [3.1.0] hex-3-en-2-one (42) outline
by Russel and Stevenson,28 conversion of 39 to the cru
bromoketal (40) was Accomplished only after allowing
bromination to proceed at 250-380C in ethyle l9 gl
stead of at 00. Further modification of the basi
dure was found necessary in the s quent step
reverse addition (pinchwise additi odiu
P to a DMSO solution of 40) app be a
edition for obtaining a r

hhthe 6Lylene l1 (41









SH4O affording 42 in 58% yield. Subsequent treatment of

42 with trimethylsulfoxonium ylide afforded 26-a and 26-s

in 66% yield; however, the syn-anti ratio proved to be

2:98, a result which was not totally unexpected.

The synthesis of 42, a monohomocyclopentadienone,

catalyzed an attempt at the preparation of the correspond-

ng tosylhydrazone from which the carbene of 42 could ul-

tely be generated. The attempt met with failure because

sy1hydrazine destroyed the carbon-carbon double bond in

1 addition fashion. This result agreed with similar

s reported by Kirmse who observed that various cyclo-

nones and cyclohexenones underwent addition as well

ndensation in reactions with p-tosylhydrazine.29

The synthesis of syn and anti tricyclo [5.1.0.03,5

ones, 49-s and 49-a, outlined in Scheme IV, repre-

ynthetic Sequence developed by Lambert, Koeng,

a.30 Although Lambert had removed a substantial

the ci-, cik-tricyclo [5.1.0.03'5] octyl-2-

acid (46) from the mixture of cis, cis and

ns acids (46) by fractional crystallization, no

w made in this work to separate isomeric tricyclic

until arrival at the ketone stage. Birch

o of benz c id afforded 1,4-dihydrobenzoic acid

hi s with ethereal diazomethane. Methyl-

te product of methylation with










Scheme IV


CO2H
1 2


Na/NH3
EtOH
CO H
2


CH2 12

Zn Cu
(3 runs)


10% NaOH
------>.3


CO2Me


45









LiA1H4
Et20


OAc


CH2N2

Et20


CO2Me



I I










V continued


syn:anti
77:23


49-s
'V.


.49-


TosNHNH2
EtOH


TosNHNH2
EtOH


50-s
rV


N-NH
I
Tos
NaH
THF


,7H
.TH FP


N-N-Tos


N
Na


S

6LS~


51-s
b'





I



diazomethane, was cyclopropanated twice by three-fold treat- 1
ment with methylene iodide and a zinc-copper couple. The
product mixture, largely cis, cis and cis, trans-methyl-
tricyclo [5.1.0.03,5] octyl-2-carboxylates (45), was con-
verted to the corresponding mixture of acids (46) with 10%
sodium hydroxide solution. Decarboxylation of 46 with lead
tetraacetate afforded the isomeric tricyclic octyl acetat
(47) which were subsequently reduced with lithium aluminum
hydride to a crude mixture of the alcohols (48). Oxidati
of 48 with the Jones reagent provided the tricyclic octa
49-s and 49-a, which were separated and purified by fou
consecutive short-path distillations. The syn-anti
of the ketones was determined to be 77:23 from t
Conversion of 49-s and 49-a to the corres
tosylhydrazones was accomplished although the

not good. %O-tricyclo [5.1.0.03,5] ocfn-2-
zon -( ) wa iin 42% yield le t
hydraZone T i n 'Ty
quest conversion 50 ot
51-s and 51-a ished e
that *ffLh o
33-a.





S27


eptanones 26-s and 26-a. Employing Eu (fod)3,

,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedione)
(III), lanthanide-induced shifts produced some
resting spectral changes, the most interesting

demonstrated that the two protons adjacent to the

ion (a-methine cyclopropyl protons) in both
ere t located farthest downfield in the

Ir s ctra. It appeared that the protons most de-

in stems were the two protons located at

ine cyclopropyl protons. Further,

tions of the agreement factor R31a-c for the

afforded values of 0.16 and

2 'respectively. It was also

erdo protons at C-3 and C-7 in

upfield than the endo protons of

the opposing banana bonds
>Wrting a shielding effect
Oi4 the geometry of 26-s 4x-


of 26-s and 26-a brought to

hex-3-en-2-on (42) where

t ~ clopropy

he yclopropyl
s might









o




1 H
H exo

HB

42 42-r


of the suitably disposed double bond. Since (42) has a

resonance form (42-r) which places a positive charge adja-

cent to the B-methine proton, it may be unfair to use (42)

as a model for analogy with regard to 26-s and 26-a. Never-

theless, the observed effects in the nmr of 26-s and 26-a
serve to create speculation about the possible contribution

00 0 0 -


6 N4 "
o o
1 2 6

26-aa 26 26-r



of a species which possesses finite partial charge separ

tion as in 26-r. The extreme case, of course, would be

contribution from the anti-homoaromatic species 26-aa.
The nmr spectra on the following pages demonst

thele eap-frog" effects ich occurred upon the addi

to eit&r 26-AI














- -ta


I I


3,


I


b.


w


C\



I





0-


t--




C\j
0






0
o









U
r-

I-)



c4-


0

S-
E
f-






i-
c-















3:


co

3:









































































II


L - ....--- -- .. .. ----




r l'q


C\J



4O






E



r=-


L-
.-




sL








q


\\


1--




L


V



































--
-- --


.8


8 1 ...: .- -.-- ....


l. I


I
Ci

c-,
0




C
Q)














0
C


LO









0
4-














0
5-























N


O
0










'-
I-I



(-
>*















rO - I~- --r- -- --* 1- - l









,Oq








; ,;~ I.










S 0


I ,. I
i--I- *r .









U)




I.,.


II '. I




.. i

I;L
































































1 -I


I -


&


:1Ii


I-


_____ __?___ _




37

























S-
"2









o




0












*-







38





























o
SI---




























L.J
0




















LL.
--. i- -





o Ca






LU


I, 0











: i














CHAPTER III

PYROLYSIS OF p-TOLUENESULFONYLHYDRAZONE SODIUM SALTS


Simple speculation concerning the probable products

from both the tricyclo [4.1.0.02'4] heptan-5-

dthe tricyclo [5.1.0.03'5] octan-2-ylidenes led

on a moderately volatile products were

ibilities. With this in mind it Jas concluded

S4I0iues which avoided solution work and

on lems would be preferred. -The method

eared to,b J:igh-vacuum pyrolysis of the neat

Idium alts wQAe, for the most part, pyrolyzed

three elected procedures. The fore-

xtr, tion of the static technique
17,33
works ch as Schecter,17'33 was

op-stati t(_-S) tec niqut oin which con-
f the sodium s a aed g ss

v um (7 x 1 mm) was ac-
vir 11y a cuum unit

for ing, and

f opera-

ttech n i q u e ,


9


























































II


~I


.C 0r
U V)


0*-

E Ta
3 C

E "-
3 u
U *r-
r, C
> f0


,-
VI
1i

.0
*r- I-

- 0
o


Q- 0


CL


r- 0)
0 C.
u
o m
U
0 E

01
1--- >
-

LL


-0










comT ly referred to as the "hot tube" technique. This

technique, in comparison with the D-S technique, allowed

fo longer contact times thereby increasing the chances for

other rearrangement of initially-formed carbene products.

e f al technique was simply the infrequently-used static

hnique which did find one important application re-

in the isolation of an elusive compound (54-c).

y solution rk performed involved several trapping

ions involving the syn-tricyclo [4.1.0.02,4] heptan-5-

-cies apstyrene or dimethyl maleate.

of pyrolysis work, involving the sodium

51-s and l-a, was performed on 34-s and

t was hoped that the different disposition

ring serve to alter the product

in g e syn to the anti carbene in

prove to be the case. In fact,

anti reactivity for each series


IO simple static (S) pyrolyses

ge' O0-500C afforded a white,

rply at 46o-470, which was conve-

cold finger (0-100) of the modi-

e and S pyrolyses. The waxy

odor whicP always served to

pyrolysa ,The solid










discolored upon exposure to air, assuming a yellow-brown

coloration within one hour. The thermal stability of the

solid appeared suspect since attempted sublimation under

high vacuum of impure material led to tarring. Heating
the solid in benzene or toluene at temperatures > 500 even

under argon or nitrogen also had a deleterious effect.

The structure of the solid was established by spec-
troscopic evidence and analysis. Infrared bands at 3020,

1650,and 650 cm-1 indicated the necessary double bond
feature. The nmr spectrum, perhaps the most confirmative

piece of spectroscopic evidence, showed a four-proton

multiple at 6 2.33, a two-proton multiple at 2.35-2.90, a
four-proton multiple at 3.02, and a six-proton multiple

at 5.55. The two-proton multiple was overlapped on each

end by the adjacent four-proton multiplets. The uv spec-

trum showed a Xmax at 254 (E 8120). The uv absorption maxi-

mum corresponded rather well with that reported for tricyclo

[9.7.0.02,10] octadeca-5,9,11,15-tetraene (53).34 Mass

spectral analysis showed the parent peak to be m/e 184.

Elemental analysis proved satisfactory for a C14H16 ole-
finic hydorcarbon. The structure therefore assigned to

this unique product was tricyclo [7.5.0.02,8] tetradeIa
4,7,9,12-tetraene (52).








Xmax = 254 max = 252
c = 8120 c = 8600



m-7


52 53



Hydrogenation of 52 resulted in the uptake of four

moles of hydrogen, the hydrogenated product clearly possess-

ing the parent peak of m/e 192. Attempts to form Diels-

Adler adducts with maleic anhydride, dimethyl acetylene-

dicarboxylate, and tetracyanoethylene failed, resulting

in the tarring of dimeric 52. This failure to form a

suitable Diels-Alder adduct was disappointing due to the

effort spent in trying to achieve the desired result; never-

thcleS, it may very well be distortions of the molecular

rework in the vicinity of the butadiene moiety are pro-

ting the 2 + 4 cycloaddition.

An interesting facet of the isolation and charac-

ization work of 52, formally the dimer of 1,2,5-cyclo-

atriene (20), is that the dimer is the major product

all pyrolytic conditions, irregardless of technique

mperature. In light of this fact, the monomeric

20 would deserve consideration as the primary prod-

ng from collapse of both tricyclic heptany-
nes via a unique six-electron pericyclic reaction

inf 6




44 V




Volatile products isolated from the D-S and S py-

rolyses of 34-s and 34-a included toluene (57), cyclohep-

tatriene (56), and two much more interesting products,

trans-ethynyl-2-vinyl-cyclopropane (54-t) and 4-ethynyl-

cyclopentene (55). Glpc analysis empqbying a column

perature of 68-70C provided analytical samplMs of 54-t












54-t 55




and 55. The cyclopropane

in the temperate range

appearing only
nmr spectrum
wi t hAi









as being destroyed. In fact, until the actual isolation

f 54-c, the assignment of trans sterochemistry to the

glpc-purified cyclopropane hinged upon this observation as

well as the known instability of both cis-1,2-divinyl-

cyclopropane (68)35 and cis-l,2-diethynyl-cyclopropane (69).36
The ir spectrum of 54-t showed the necessary mono-

substituted-acetylene bands at 3320 and 2120 cm1 with the

vinyl absorptions displayed at 1635, 980, and 905 cm

The 100 MHz nmr spectrum at high field showed a three-

proton mulitplet at 6 0.80-1.40 (H6, H7, and H8), an ace-

tylenic doublet at 1.85 (H5), and an allylic multiple at

1.58-1.94 (H4). The olefinic regions displayed an ABX pat-

tern with multiplets centered at 4.96 (H3), 5.12 (H2), and

(H1). Coupling constants afforded by first order analy-
are given below:




1 H J = 16.8 Hz
H 1,2

7 H 31,3 = 9.5
2 ,4 = 7.5

4 J2,3 = 2.5

J = 2.0
5,6


54-t









Mass spectral analysis' of 54-t demonstrated the

parent peak to be m/e 92, the parent peak also being the

base peak. Elemental analysis in turn proved satisfactory
for the C7H8 olefinic hydrocarbon.
The assignment of the 4-ethynyl-cyclopentene (55)

structure resulted from comparisons with the reported spec-

troscopic data of 55 which was isolated by Cristl and
Harrington as the major product from the pyrolysis of n

tricyclenone p-tosylhydrazone sodium salt (58).37 The ir
-l
spectrum of 55 displayed bands at 3325 and 2125 cm" ,






Na ( 1600

N Tos

58 55*




dicative of a monosubstituted acetylene. The c
the carbon-carbon double bond was supplied by p
and 690 cm-1. The 60 MHz nmr spectrum sh d

doublet at 6 2.04, a five-proton multi e r

3.20, and an olefinic singlet of two ro
5.68. Mass spectral aiaysis









the base peak, to be m/e 92. Elemental analysis proved
satisfactory thereby confirming the structure of 55. It
should be noted that flow (F) pyrolytic work led to in-
creased yields (6.9-25.9%) of 55 in comparison with D-S
work.
The fourth and final true carbene product, discount-
ing cycloheptatriene and toluene as bona fide carbene prod-

* ucts, to be isolated from pyrolyses of 34-s and 34-a was
cis-l-ethynyl-2-vinyl-cyclopropane (54-c) in 17-23% yield.
This elusive compound was successfully generated by a simple
modification of the basic static technique. Maintaining the
sublimator cold finger at -72 to -650C, twice the normal
Amount of given sodium salt usually employed was heated
from an initial temperature of 1400 to 2250 over a period
thirty minutes. For the first time, the diazo precursor,

or anti-5-diazo-tricyclo [4.1.0.02,4] heptane (59) was
Served to have bE5n conveniently generated and trapped
(on thqocold finger). Coinciding with the observation of
e red diazo compound was the successful isolation of 54-c,
ecies of unusual reactivity. Whereas 54-t proved ther-
ly stable at 1590C in deuterochloroform solution, 54-c
rwent complete rearrangement within thirty-six hours in
rochloroform solution at 250 to afford 52. The impli-
ns of this rearrangement upon the nature of the primary
t obtained from collapse of the carbene to product
nable. At this point, although no hard kinetic
n able. At this point, although no hard ki-netic




A&A









evidence is yet available, it appears that 54-c has a half-

life in solution of perhaps two to three hours maximum,

assuming the unimolecular process, 54-c--+20, to be rate

determining.

The syn-and anti-5-diazo-tricyclo [4.1.0.02,4]

heptanes (59) proved extremely unstable, appearing to Pery

slowly lose nitrogen even at the low temperatures employee

This was not surprising since secondary aliphatic diazo '

compounds had generally been demonstrated to not survive

the pyrolysis conditions wrien generated from the correspond-

ing p-tosylhydrazone salts. Moreover, the instability f of

59 was in accordance with the reported instability of di

cyclopropyldiazomethane (60) which must be kept below -3

in order to sufficiently retard decomposition.38







N2





49




The ir spectrum of 54-c showed diagnostic absorp-

at 3310, 3085, 2120, 1635, and 985 cm-1 although in-

ence from cycloheptatriene and dimer 52 tended to ob-

absorptions elsewhere in the spectrum. The 100 MHz

ectrum at high field showed two one-proton multiplets

78 (H8) and 1.20 (H7). A two-proton multiple region

observed at 1.48-1.84 (H4 and H6) for the allylic and

1 protons followed by an acetylenic doublet (H5) at
olo finic regions displayed an ABX pattern with

centered at 5.10 (H3), 5.24 (H2), and 5.64 (H1).

stants are given below:




62= 15.8 Hz

J = 8.5 Hz
1,3

Ol 4 = 7.5 Hz

go J2,3 = 2.5 Hz

2 = 2.0 Hz
HH 5,6
SI









r nmr analy 'of both
vided d ethy-









In an initial attempt to trap the key reactive in-
termediate, 1,2,5-cycloheptatriene (20), pyrolysis of 34-s
via the D-S technique was effected under high vacuum (9 x
10-5 mm: maximum pressure reading) employing a matrix iso-
lation unit, with the matrix window maintained at 60K as
the pyrolysate trap.* Inspection of the uv-visible range
200-500 nm showed the only readily discernible absorption
to be due to 52, Amax 254. Ir inspection showed principally
the presence of the cyclopropane 54 and dimer 52. A peak at
2040 cm- with a shoulder at 2035 cm-1 was of primary inter-
est although without considerably more work in this area it
would be extremely premature to assign the absorption to a
high-energy allenic stretching mode which would probably be
characteristic of 20.
Several attempts to trap the monomer 20 with sty-
rene and dimethyl maleate failed. The products obtained
from these reactions were the spiro adducts resulting from
trapping of the carbene itself. Heating 34-s in the pres
ence of either styrene or dimethyl maleate in tetraglyme
solution afforded the respective adducts 2-phenyl-s iro'
[cyclopropane-1,5'-syn-tricyclo [4.1.0.02,4] heptane] (6
and trans-2,3-dicarbomethoxy-spiro [cyclopropane-1, sy
tricyclo [4.1.0.02'4] heptane] (62). o h



re matrix 1
se of mat
es of Dr. o
i versit










SMe02C CO2Me





61 62



S(34%) and 62 (39%) were not spectacular, they were

eless sufficient so as to allow characterization of

cies.

The mass spectrum of 61 showed the parent peak to

196 with elemental analysis proving satisfactory for

enoid hydrocarbon. Peaks at 3070, 3040, 1605,

indicated the presence of a monosubstituted

ear atic structure while an absorption at 3010

the tyclopropane structural feature. The

informative since a set of overlap-

tIt at 6 2.15 and 2.30 provided evidence

1n isomeric mixture consisting of cis,
1. The 60 MHz nmr of isomeric 61








t-61









showed two four-proton multiple regions at 6 -0.05 0.730
and 0.75 1.93. The spiro cyclopropane hydrogens gave rise
to (a) one distinguishable doublet at 1.25 and (b) the set
of overlapping triplets previously mentioned. The high-
field triplet had a coupling constant of 7.5 Hz while the
low-field triplet possessed a coupling constant close to
7.0 Hz in magnitude. The uv spectrum displayed B-bands at
262, 267, and 276 nm with a much more intense K-band at 22
nm (E 7490). The K-band, while 22 nm higher than that of
benzene was reasonable since cyclopropylbenzene itself s
a K-band at 219 nm (E 8900).40
The assignment of trans stereochemistry to the
spiro dicarboxylate 62 was based on the size of the coup
constant obtained from the AB quartet generated by the
cyclopropane hydrogens in the 60 MHz nmr spectrum. T
Hz splitting observed corresponded well with the 5
splitting reported for dimethyl-3,3-dimethy c
tranl-1,2-dicarboxylate (6). 41 Further th*,Qcs
cyclopropane dicarboxylates 64-c and 64-t have re
H3C CH3

H CO2CH


02CH3 H CO Me MeO2

S63 g6 .




53




f 8.8 and 6.6 Hz, again confirming the trans stereo-
stry of spiro adduct 62.4 The 60 MHz nmr of 62 dis-
yed two four-proton multiplets at 6 0.52 and 1.70, the
roton AB quartet with'doublets located at 2.42 and 2.65,
two three-prpton singlets at 3.72 and 3.76. The mass
tum showed a very weak parent peak (< 1%) but the base
*1 +
t m/e 117, corresponding to C9H9 demonstrated the
loss of formally two carbomethoxy radicals and one
atom. *Th ,r spectrum showed particularly strong
1 -1
ons 't 1740 1440, 1340, 1290, 1230, and 1165 cm 1.
yrolyses ~ yn- andanti-tricyclo [5.1.0.03,5] octan-
y1hydrazon odium salts, employing-the D-S tech-
ded lro products in variable total yields rang-
79.9% to a low of 26.5%. The range of
s from 2600 t6 4000C with product
ur vicinity of 4000. The primary
o b' cis-l-allyl-2-ethynyl-cyclo-
it5 hy rogen-shifted derivative,
rowing in yield with corre
lysis temperature. 0
65 owed a one-proton multiple
t-proton multiple at 1.02
j
otb l tiplet ai 1.38
laye t 1.81 (H 5
V 1 I









The vinyl protons gave rise to an ABX pattern with multiplets
centered at 5.02 (H3), 5.10 (H2), and 5.95 (H1). Simple

first-order analysis supplied the relevant coupling constants:


H6 J = 17.6 Hz

8 HC 7 H
1 J = 9.7 Hz

H3 l ,4 = 6.4 Hz



H5

65
65




The ir spectrum of 65 showed the necessary acetylenic a
sorptions at 3320 and 2120 cm l with the vinyl contrib
-1
displayed at 3080, 1645, 990 and 910 cm 1. The ma
trum showed the parent peak to be m/e 106 with
located at m/e 91, C7H7 Elemental analysis pr
factory for the C8H10 compound thereby establ"
identity of the hitherto unknown 65.
The acyclic octatetraene 6, predo
in the pyrolysate, was established

ived from a 1,5 hv rogen shift in c
&.sol oduct derived frQm









dent flow (F) pyrolysis of glpc-purified 65 at 410.
e octatetraene was obtained in 72% yield as the only

eadily-identifiable product with no trace of 65 in the py-

rolysate.
The 100 MHz nmr of 66 showed a pseudo heptuplet

f two-proton magnitude at 6 2.84 (H3). The olefinic re-

ion was more complicated giving rise to a two-proton pseudo

entuplet at 4.74 (H1), a three-proton multiple region at
4.84-5.32 (H2, H7, and H8), and another three-proton multi-

plet region at 5.50-6.60 (H4, H5, and H6). The proton as-

signments appeared justified on the basis of comparison with




HH1 H H 7
H 5


H
667






H3 H3

66 67


um of e reasonable model compound 1,2,5-

atr 6 .43 The ir of 66 possessed an absorption at

Srm f tha allene moiety. Other important








absorptions attributed to carbon-carbon double bond group-
ings were noted at 3090, 3005, 1645, 1605, 995, 910, 845
and 740 cm-1. The uv spectrum provided an absorption maxi-
mum at 225 nm, e 27,100. Since no compound possessing a
cis-butadiene structural feature has been demonstrated to
have an extinction coefficient greater than 10,000,4 it
appears that 66, if a cis-trans mixture, contains a sizable
trans component. Mass spectral analysis placed the pare
peak at m/e 106 while elemental analysis proved satisfact
for the C8H10 isomer.
A summary of the basic reactivity of the syn add
anti tricyclic heptanylidenes and octanylidenes shows th
four C7H8 monomeric and dimeric species and two C8H10
meric species were isolated. As yet unanswered are
stereochemistry of the ring fusion in 52 and (b)
metry of the butadiene moiety in 66. Probably th





5 5
52 54-c 54-t
b 6w9
rP l




57




ing products in terms of continuing interest are the

ic cyclopropanes 54-c and 54-t. Kinetic studies of

ompounds will extend the body of knowledge surrounding

Cope rearrangement. Although not mentioned earlier, 54-t,

h having proved stable at 1690C in solution, did rear-

q quantitatively to give 52 at 2080 in solution as evi-

ed by uv and mass spectral fingerprints. Moreover, it

appear that 54-c, even without further kinetic exami-

will een cis, ,2-divinyl-cyclopropane (68)

s-1,2- i hyn -cyclopropane (69) in proclivity towards

ype meant .35 6L6








69



ser of cycloheptatriene and

te ob ined from the tricyclic heptan-

sonable to say that the cyclohepta-

tonated 5-diazo tricyclic heptane

wed by cationic re-

This hypothesis

ium or




58

4 4


carbonium ion intermediates (or both) obtained from p-

tosylhydrazone salts when decomposition fails to exclude
2
a protic environment. The formation of toluene, which

could derive from cycloheptatriene at high temperatures as
45
outlined by Woods, is also due in part to the breakdown

of the p-toluenesulfinate anion since toluene was also o

served in the pyrolysate afforded by the tricyclic octan

ylidenes. The end result is that cycloheptatriene and t

uene are not carbene-derived and warrant no further di

s ion.



2 H

-N2



70

>40


C CH.













CHAPTER IV

DISCUSSION AND CONCLUSIONS



d The question of paramount importance with regard to
e isolation and characterization of the various products

ived from the syn and anti tricyclic heptanylidenes is

intriguing one: Do the observed products stem from the

collapse of the carbene to 1,2,5,-cycloheptatriene (20)

owed by rearrangement and/or dimerization, or does cis

hynyl-2-vinyl-cyclopropane (54-c) merit designation as

le primary carbene product undergoing subsequent re-

ment to afford the other observed products?






S? ?


0 54-c
4


T answer to such a mechanistic question must be

(a ervations thus far obtained (Chapter

(bpea'ing in the chemical literature.








Analogy or precedent was afforded by the remarkable insight
of Sasaki and coworkers who proffered a novel explanation
for the considerable difference of the carbene product dis-
tributions between the aldehyde and ketone p-tosylhydrazones
71 and 72.46 It was concluded that the chrysanthemyl carbenes



3
--- + H C=CH
2 2 2
CH=NNH Tos
71 (cis and trans) 68-73%


K __ -- 1r
2
SC=NNH Tos C3
CH
3
72 (cis and trans) 70-92%
derived from cis and trans-71 underwent largely fragment
as opposed to ring expansion due to a favorable electronic
effect imparted by the isobutenyl moiety. The electronic
effect would result in the lowering of the transition-sta
energy for the fragmentation process by virtue of format
of a conjugated diene, assuming the carbene reacti r
ceeded via either a concerted process or via a s
process involving either an ion-pair or radical




S* 61








H
I0

0 O,


H* _



radical pair ion pair


e of the chrysanthemyl carbenes derived

-72, the ring expansion process predomi-

sive migration of the isobutenyl-substituted

d), again suggesting that the electronic
isobutenyl substituent'plays an important role

ion state. However, another piece of rationale

der to explain the drastic difference in

uct s ibutions despite obvious electronic

th yl -substituent. It was Sasaki's con-
t i y of cyclopropylcarbene reactions,
0 I11ti dr ring expansion, had been explained

o tipn of strain and electronic fac-
eration of conformational effects.

hat the co-formational effect played

n Qptermining the cyclopropylcar-

y. Maximum interaction of the

nd (the ring-expansion process)
1 uent R ca mud-an s-trans-like

pane i while an








s-cis-like conformation afforded poor interaction, presum-
ably facilitating fragmentation as the process of choice.


Rc

R3 R3
RR

c

S-trans s-cis



1 1

R3 RCR ------ Rc


R2 R2 R3



The observed ring-expansion of the chrysanthemyl
carbenes of 72 was thus rationalized on the basis of the
s-trans conformational effect while the chrysanthemyl car-
benes of 71, minus the methyl substituent, were free to C
assume either conformation, the s-cis being probably no
more or no less favored than the s-trans with the elect
effect exerted by the isobutenyl moiety being the dec si
factor.
,,a _









The development of the conformational effect as a
n determining the cyclopropylcarbene rearrangement

ude was further extended by Sasaki to geometrically
rained species, some of which are locked into either
-trans or an s-cis conformation. Whereas 73, an s-trans
:ies, underwent ring expansion exclusively, 74, 75, and
underwent the fragmentation reaction due to the s-cis
picture presumably.46





(CH2)n

74
73 n = 2,3

(CH2)
r^ n






75 76



s precedent as provided by Sasaki would re-
inyl cyclopropane (54-c) as the pri-
y to be obtained upon collapse of
anyl i~ species to product. Cursory
e t s outlined in Chapter III would









tend to argue in behalf of 54-c as the sole primary product
since 54-c, once formed, pauved extremely labile (t1/2
2-3 hours maximum) at 25 rearranging smoothly to dimer 52.
Further, at present, there is no evidence to argue for re-
versibility in the formation of monomer 20 with the pre-
dominant formation of dimer 52 under all pyrolysis condi-
tions arguing for an essentially irreversible reaction lead-
ing from 54-c to 52. The simple kinetic picture suggested
by the observed reactivity of 54-c is supplied by the follow-
ing reaction sequence treated by the steady state approximaj
tion:13

k k3 I
2C 2M --- D i
k2


rate = d[D]/dt = k3 [M]2

d[M]/dt = k1 [C]2 k2 [M]2 k3 [M]2 C = cyclopropane 54-c

= 0 M = monomer 20

[M] = kl/2 [C]/(k + k3)1/2 D = dimer 52
1 2 3)

d[D]/dt = klk3[C]2/(k2 + k3)



Assuming k2 << k3, the rate expression w Id
to d[D]/dt = kl[C]2, the rate of formation of t
to 0 Am Ahk[C











The intermediate, once formed, goes on to product rapidly.

In this situation no equilibrium is established between re-

actant and intermediate, the intermediate (M = 20) being

dubbed a van't Hoff intermediate: Mechanism A.


S.-
s=
u


4-

0
0J
Q-


Reaction Coordinate


k3
3


4-c
L 1


spite the foregoing discussion of precedent and

g qualitative kinetic analysis, there remain some

ionstied into the exact identity of the







I &


..


k

k2







I

primary product obtained from the tricyclic heptanylidenes.

Assuming 54-c to be the primary product, how does one ac-

count for the formation of trans-l-ethynyl-2-vinyl cyclo-

propane (54-t) and 4-ethynyl-cyclopentene (55), products,

which if they arise from 54-c, must do so by a nonconcerted

process presumably involving biradical intermediates; i.e.,

54-c would be forced to undergo epimerization via cleavage

of the C1-C2 bond to afford 54-c at lower temperatures

(1600-400C), while a 1,3 alkyl shift involving migration of B

the C1-C2 bond would afford 55 at higher temperatures

(> 5000C). In reality such reactivity for 54-c does not A









nstrates the facile nature of the six-electron peri-
lic reactions for such substituted cyclopropane systems.35,36

ever, in the case of 69 surface-catalyzed reactions in the
s-phase kinetics cast doubt on the exact nature of the re-
angement of 69. In contrast to the foregoing purportedly
certed pericyclic reactions, the cis-trans isomerizations
simple cyclopropanes typically afforded Ea's in the range

).4-65.5 kcal/mole while 1,3 alkyl shifts of simple vinyl-

propanes gave rise to Ea 's in the range 44.5-54.6 kcal/
48


0

(S Ea = 60.5 kcal/mole

D



-- Ea = 49.6 kcal/mole




o be made is at the heart of the discussion of
le anisms: if 54-c is the only true primary
54g. and musIt derive from a species other
e s ime, the low yields of 54-t (1,0-
.8-254 s est that the importance of
illm+C wvver deserving of mechanistic scrutiny,




68




should not be overly weighted so as to create havoc with
the mechanistic pathway proving, in the final analysis, true
for the tricyclic heptanylidene systems.
The suggestion to be made at this point is to also
consider an alternative mechanism which could account for
the observed products. In this alternative mechanism, 1,2,
5-cycloheptatriene (20) would arise via a novel six-electron
reaction involving the carbene site and the C1-C6 and C2-C4
cyclopropane bonds, a postulate only briefly mentioned ear-
lier in Chapter I. The application of the Mobius-HUckel
concept as applied to organic molecules and reactions by
Zimmerman49 to the cyclic arrays involved in bond-breakin
and bond-forming processes in the transition states of th
tricyclic heptanylidenes shows that both systems posse
HUckel orbital arrays with the syn isomer (19-s) having
zero sign inversions while th anti isomer (19-a) po
four inversions. This is schematically outlined
The result of this simple analysis is the tendency
the fact that either carbene could afford t
species 20 outright without invoking an interme
as 54-c. It should be noted tha e foreg

arrays employ tAe p2 configurati the
sumptio which tter alomm the dev
nco ed in n
it 0 .ene










/ Bond breaking



Bond forming
syn


Bonds unchanged




S anti dark lobes: + of basis set
light lobes: of basis set




ular models. Another examination of the possible
ness" of this carbene arrangement would be afforded
olching the hypothetical arrangement from the view-
gta a tetro-cycloaddition involving a Tt4s + T2s proc-
r 1-s and a T4a + r2a process for 19-a wherein the
tive T groupings have been tagged with the HOMO-LUMO
nations derived from the Fukui Frontier Orbital ap-
to pericyclic reactions. The connecting lines
slof the same phase serve to demonstrate the
facial-antarafacial interactions which af-
ene from the respective carbenes. Again it
notd tha he p2 configuration of the carbene
q P6,







2 + 4 retro-cycloaddition:


Lumo


T4S + I2s Homo






4rr4a + Tr2a
---a--71a


anti -

has been employed in describing the electronic interactions

leading to the allene as product. The exact configuration

of the carbene carbon in the tricyclic heptanylidenes as

well as the electronic makeup of the allene 20 will be dis-

cussed further videe infra), but first a hypothetical pic-

ture must be drawn based upon the primary formation and sub-

sequent reactivity of 20: Mechanism B.


k3


Cope

k2----
ki


K 54-c


?55






55


S54-t
ru--


syn









Since it hasbeen experimentally established that

arranges smoothly to 52 presumably via 20, then 20,

irst formed as specu ted, would be in equilibrium with

ble 54-c he rate'determining step being that leading

at dimer 52. In this sense 20 would be an

ius 9 Bediate3 and the energy profile would quali-

ly appeagas follows. Further, an understanding of

rigin of p ct 54-t and 55 would be more easily


M = 20


C = 54-c


D = 52


oordi nate


My formed species 20 could be
I and triplet states, the triplet

en-chain biradical species 77

4-t or depending upon ,the

Si"ce both singlgj
1 1 2
d for c ns general, 12
dp._










it is reasonable to assume that a triplet tricyclic heptan-
ylidene species would give rise to a triplet allene species

which could then fragment to give biradical 77. A biradical
such as 77 is a potential intermediate as evidenced by the
assumed formation of such intermediates in the pyrolyses
of (a) the salt of bicycle [6.1.0] nona-2,4-6-triene carbox- 0
aldehyde tosylhydrazone (73)51 and (b) 7-cycloheptatrienyl
diazomethane (79).52




Na I
78 CH N-N-Tos -CH













79 CH = N2 C-







_0)









Contrast of the preceding discussion of Mechanism B

st Mechanism A points to the fact that triplet 20,

ined in Mechanism B by collapse of a small triplet com-

onent of the tricyclic heptanylidene to triplet 20, would

not be allowed under Mechanism A since, under the concerted

process assumed taking place in the conversion of 54-c-20-
2, singlet cyclopropane (54-c) would give rise to singlet

which would dimerize as fast as it is formed.
Two alternative mechanisms have thus far been pro-

sed. A clea choice between the mechanistic alternatives
be left to the individual reader at this point. A

r chanism, which.would invoke both 54-c and 20 as
ry products via competitive formation from the carbene,
tO beg the question of mechanism, and


s and electronic character of 20, the
f tricyclic heptanylidene chemistry, de-
I o eration. The smallest cyclic allents
rf 1,2-cyclononadiene53 (80) and 1,2,6-
81). Thg smallest cyclic allene yet ob-
exadiene (22) with 1,2-cycloheptadiene
terms of framework distortion. As
Chat the observation of 21 and
ion of their dimers and tetramers
14a-b,15a-b
trapping experiments.

h&IA I











0 4d
80 81


In the smaller ring systems such as 21 and 22 the various
*authors have presented the vierwoint that these systems
must be something less than a fully-bonded allenic structu
i.e., research groups such as Ball and Landor14a and Moo
and Moser 4b have proposed that the C6 and C7 cyclic all
possess a planar structure in which carbon atoms 1,2, an
are sp2 hybridized with unbonded electrons for the sing
species (S) residing in the hybrid orbital at C-2, w
in the triplet species.(T), one electron has been p
from the nonbonding hybrid at C-2 to the nonbonding
orbital.
Mol cent Dil nd UndOrwo
MO calcula I imber is
allene as and mal 1
the lowes
effect
tr u t i n a
















basis set: dark orbitals: S T
in plane
light orbitals:
out-of-plane

-2. On the other hand, 1,2-cyclohexadiene was shown by the

Iculations to most likely possess a triplet ground state

st approximated by an allyl radical with a second unpaired

ectron occupying the in-plane orbital at C-2.

Returning to the question of the initial carbene

configuration of the tricyclic heptanylidene, it can be

at the singlet p2 configuration assumed earlier (note

-Mobius and 2 + 4 retro-cycloaddition schemes) would

ise to a-specifs formally containing an allyl anion

sitiwl charge residing in the in-plane orbital at C-2.

angement of the singlet species disagrees with pre-

n.54 On the other hand the lower-energy 2 configura-

f the carbene, because of its disposition away from

clopropane bonds (Cl-C6 and C2-C4) would not








high energy singlet

A*







allow for the necessary overlaps in the transition state 0
leading directly to monomer 20. In fact such an arrangement





( D


a2 low energy singlet


would most likely afford 54-c, the primary product of Mech-
anism A, since no other reaction appears possible. Thus
determination of the singlet carbene configuration (a2
p ) for the tricyclic heptanylidene might aid in the ch
of mechanistic alternatives. On the other hand, it
remembered that the demonstration of p2 character i
benes such as the syn and anti tricyclic heptanyll
not guarantee subsA4ljnt Inique reactivity as would b
served in asi of Mechanism B where the
tion, asru shocm l iati sup pose'dl o
six-elect ric(i- c' t n leading
tion arises f. gman>l s nmen f1 o
to 15, discuss in Ch ter which under
Slashed f K^ pro asd t
cycl ic pr
b VP




W T


W The point to be made in this discussion about the
electronic structure of 20 is that 20, if the primary
Orbene product of tricyclic heptanylidenes, must arise by
what appears to formally be a bishomoaromatic carbene in a
singlet process and would possess at least initially singlet
character reverse that of prediction.
As a matter of final interest, it would be of value
to attempt to place the key C7H8 species on an energy sur-
face although it would be only a crude approximation in the
case of both 20 and the tricyclic heptanylidenes themselves.
__ 55
employing Benson's additivity rules55 for the estimation of




b
135

102 1 89-90

65 66


"strain free"









thermochemical properties, 54-c, 54-t, and 55 are easily
calculated allowing one less kcal/mole for the heat of
formation of 54-t due to the missing cis interaction as
would be observed in 54-c. The straightforward calcula-
tions afford values of 90, 89, and 66 kcal/mole for 54-c,
54-t, and 55, respectively. Employing Wentrup's extra-

polation56 of Benson rules to carbenes, a rough calcula-
tion of the energy of the tricyclic heptanylidene species
itself employing the heat of formation of triplet methylene
(92 + 1 kcal/mole) for the carbene "group" affords a value
of ca. 135 kcal/mole. Ring corrections used in obtaining
this value are derived from bicycle [3.1.0] hexane (32.7 kcal/

mole) and cyclopropane (27.6 kcal/mole). The value doe
not appear altogether unreasonable since 7-cyclohepta-
trienyl methylene (82) has been calculated to possess a
of formation of ca. 145 kcal/mole,56 a value which s v
to indicate that the heat of formation for certain s
constructed carbene speciqj Lin be rather high.




CH


82


d a speci





4


The C7H8 species most difficult to assess on the

Energy surface is the monomer 20. Perhaps the best way to

view this species energetically is to assume the view of
57
Dolbier57 who approximated a value for diradical 20 by first

assuming a i-bond energy in strain-free 20 of 60 kcal/mole

and subsequently subtracting out (a) 8 kcal/mole for the

allene destabilization energy and (b) 15 kcal/mole for the

allyl radical stabilization energy. The resulting value

(37 kcal/mole) was added to the heat of formation of "strain-

free" 20, 65 kcal/mole, to afford a final figure of 102

kcal/mole. This calculation, while only a rough approxi-

ation, probably represents a minimum value since Underwood's

INDO-MO calculations of 1,2-cycloheptadiene (21) under-
score the fact the 21 may indeed be a "distorted"allene as

opposed to a planar species, thus by analogy raising the

energy of 20 above the 102 kcal/mole figure approximated.

il the energy diagram shows that the carbene will cer-

i y convert to productss, it is also obvious that acti-
20 should convert to some or all of the species below

n the profile. In passing it should be noted that the

52 afforded a calculated heat of formation of ca. 88

/mole, a value which is probably high due to lack of a

able model for ring corrections.

A discussion of the chemistry of the tricyclic

ocAnylidenes is essen-tially a matter of the fragmentation








process occurring for cyclopropylcarbenes. The idea that
these systems could possibly give rise to the novel cyclic
allene monomer bicycle [5.1.0] octa-3,4-diene (84) was
developed early in the work with the tricyclic heptanylidenes.





< > dimer


84


2 1
Whereas the p singlet of both tricyclic heptanylidenes
would possess to a certain degree parallel geometry with
regard to the adjacent cyclopropane rings, the tricyclic
octanylidenes in the p2 singlet state would possess th
bisected geometry which plays such a vital role }n the
carbonium ion chemistry of th(se systems.30 It was tho
that this favorable added factor might help overcome



1
R

R bise R
bisected APw aral




81

1 I-



ssary enefget i expiredd for the trishomo interac-
n leading to monome( 84. Molecular models showed
hat the syn species was especially well set for this
e of interaction.
It appears from the pyrolysis results, though,
t any trishomo interaction in these systems will have
eestablished.y ,trapping reactions with olefins and
mmett studies in order to disclose the elctrophilic-
or nucleophilicify of these systems.
The obse ce of the 1,5-hydrogen shift in the
is-l-allyl ethynyl cyclopropane (65), the
primary c'arben oduct from the syn and arnti tri-
c octanyliden s nit without precedent since
d Hop d afacile 1,5-hydrogen shift
1 cis-1-ethynyl-2-methyl cyclo-

Swhih 1l converted to hexa-1,2,5-triene









1,5













3400-5300
------>-


(67) at the above specified temperatures.58 Analysis

of conformational effects favoring a ready transfer of

hydrogen in 65 shows that the situation most favored

would have an orientation where the vinyl group of the

allyl moiety is oriented away from the neighboring

triple bonded substituent as pictured below. This


situation would lead to a predomi

tetraene (66) having trans geomet


t formation o

for the bu'd









is supported by the observed uv extinction coefficient
27,100 for 66 as previously noted in Chapter III.

'In retrospect, the question of operational homo-
-omaticity in the tricyclic heptanylidenes 19-s and 19-a
in the tricyclic octanylidenes 25-s and 25-a has been
d. To fully answer the question, further work will be
red in order to demonstrate the electrophilicity or

ophilicity of said carbenes. It can be stated, however,
t such homoaromatic reactivity appears a definite possi-
y for 19-s and 19-a due to the nature of the observed
cts. The case for 25-s and 25-a is not as promising
rings to mind a mechanistic consideration which should
orted the fragmentation process of cyclopropylcarbenes
s mechanistic pathway may prove, in the final ana-
erative for both the tricyclic heptanylidenes and
idenes. The consideration afforded to the fragmen-
ts is one whereby the process may be visualized

d process employing th6 cheletropic designation;
on in which two a-bonds which terminate at
m re made or broken in a concerted fashion.47

Bsengagement of acetylene from ethylene
rba4 e as reactant has been treated by
y Lia to what is now known as
wing method.59 Recently Jones and
gantI~ implified pro the
^*ified Prob








MO following method in general which allows for better visu-
alization of the overall process leading from reactant to
transition state to product. The following are the "rules
of thumb," developed by Zimmerman and expanded upon by Jones
and Brinker,60 which are put to use in constructing the
schematic correlation diagram for the cyclopropylcarbene
fragmentation process:
(1) For the MO following, treat the carbene
as the sum and difference of two "p"
orbitals. "s" character is added after
compatibility of reactant, transition
state, and product orbitals is deter-
mined. Thus, during the "following,"
the orbitals of the lowest singlet state
of methylene would be represented by LS-1
and LS-2. Subsequent addition of "s"
character to the orbital used in the
reaction ((pl + pn) or (pI pn)) leads *
to the familiar filled sp2 orbital of the
carbene and depending on the orbital used
in the reaction, permits prediction of
the orientation of the carbene during
the reaction.

LS-1 LS-2

C C and = C


(P1 + Pn) (P1 Pn)


Add "s" Add "s"
o C to -
!Pi + Pn (Pl-Pn










(2) Number the transition state linear
array beginning with one carbene
orbital and ending with the other.

(3) Assign the familiar linear polyene
orbital signs to the transition state
orbitals.

(4) Follow each occupied reactant MO to
product, using the carbene MO that is
compatible with the highest occupied
transition state MO.
(pp. 7-9)
Thus, in conclusion of this chapter, the application

the Jones-Brinker extrapolation of Zimmerman's rules to

cyclopropylcarbene cheletropic reaction affords the

owing correlation diagram (Scheme V). The most impor-

t ob ervation52 to be obtained from the diagram is that,

"s" character is finally added to the proper carbene

ital used in the reaction (LS-1 vs. LS-2) under the

pices of rule 1, it will be added to pl + P6 (LS-1),

vertical p orbital, which correlates in symmetric

ashon with thl bonding product orbital T 34. The quali-

ve t, an important one in light of preceding dis-

n concerning the reactivity of p vs. a singlet con-

ions of cyclopropylcarbenes 19-s, 19-a, 25-s, and

i that the electron pair of the carbene must become

te n an sp2 hybrid in the vertical plane (o). Once

assumed only one mechanism is apt to derive,

tion. Closing the discussion on an opti-

Sstructure such as 19-a through the

parted by homoaromaticity, were able










Scheme V


Reactants


+* *
2 -A

023 -45

*0
c\r C


Symmetry element: vertical plane (o)
Transition State Products


* *




V M


only
----->


P s ---- sp2 (vertical) = o2


F the pi configuration. Could one reasonably assume
f e"of reaction for such a carbene? The con-
could very well be yes.

0Gp


V


-----O-


4Z-


z =














CHAPTER V

EXPERIMENTAL


Melting points were taken on a Thomas-Hoover melting

point apparatus and were uncorrected. Infrared spectra of

synthetic intermediates were recorded on either a Perkin-

Elmer Model 137 or a Model 437 spectrophotometer while the

spectra of pyrolysis products were recorded on a Beckiian IR

10 spectrophotometer. Nuclear magnetic resonance (nmr)

spectra were obtained from a Varian Model A-60-A spectrom-

eter and, less frequently, from a Varian Model XL-100 spe

trometer. Mass spectral data were obtained from both an

Hitachi Perkin-Elmer RMU-6E mass spectrometer and an AEI

MS 30 high-resolution mass spectrometer. Ultraviolet

tra were recorded on a Cary 15 double-beam spectrop

Elemental analyses were carried out by Atlan
Microlab, Inc., Atlanta, Georgia. Glpc work, analyst

and preparative, was performed on a Varian Aet

A-90-P3 gas chromatograph employing the cut-an

method of analysis in analytica ork. Four c

d in glpc work and are reference s foll

1) column A 3% FFAP o omaso

5 ft x 0.25 alumi









(2) column B 10% Carbowax 20 M + 3.5% KOH on
Chromasorb P-Regular, 10 ft x 0.25 in -

aluminum.

S (3) column C 6% SE-30 on Chromasorb P-Regular,
5 ft x 0.25 in aluminum.

(4) column D 18% DC-200 on Chromasorb P-Regular,
15 ft x 0.25 in copper.

All compounds which were not referenced were com-

cially available.

oration of diallyl ketone (29).

Tetramethyl -1,3-cyclobutanedione (27) was pre-

ccording to the procedure of Miller and Johnson:18

30-1140 (lit18 mp 1150-1160). Reaction of allyl

rd (1.25 moles) with 27 (0.50 mole) using the pro-

e of Dreyfussl9 afforded 5-allyl-5-hydroxy--2,4,4-
thyl-7-octen-3-one (28) in 55% yield (lit19 61%).
analyzed cleavage of 28 (22.5 g, 0.105 mole) em-
barium hydroxide19 followed by distillation of
lysate (bp 450-570/20 mm) on a 23 mm, 36 in
aust semi-works spinning band column afforded four
boiling (20 mm) at 320-380, 40-48, 490-550,

-560. Redistillation of the third fraction and

tion with the fourth fraction gave 7.5 g (0.068
f ketone (bp 550-56/20 mm, lit.19 bp 51-
inated with 5-10% allyl propenyl ketone.









Net yield of 29 was typically 62-64% (6.8-7.1 g, 0.062-

0.065 mole). Ir (film): 3025, 2960, 2920, 2870, 1730,

1640, 1420, 1385, 1360, 1325, 1285, 1215, 1135, 1105,

1070, 1050, 995, 920; nmr (CDC13): 6 3.23 (d with split-

ting, J = 7 Hz, 4 H), 4.90-5.32 (AB m, terminal vinyl H,

4 H), 5.58-6.33 (m, 2 H); mass spectrum (m/e): 110 (M ),
69 (M+ C3H5, major peak).

Preparation of 2,2-diallyl-1,3-dioxolane (01).

A solution of 6.95 g (0.0631 mole) of 29 in 70 ml

of benzene was mixed with 5.15 g (0.0830 mole) of ethylene

glycol and 0.05 g of p-toluenesulfonic acid monohydrate

in a 200-ml round bottom flask. The flask was fitted with

a Dean-Stark trap and a condenser (equipped with a drying

tube). The mixture was refluxed until 1.1 ml of water had
been collected (97% of the theoretical amount). The cooled
reaction mixture was washed with 20 ml of 10% sodium hy-
droxide solution followed by five 10-ml washes with watAr.
The benzene extract was dried over anhydrous K2CO3 and

the benzene removed by rotary evaporation. The residual
liquid was distilled at 20 mm affording 4.88 g (0.0316
mole) of 30 (bp 75-76, 50%). Preparative glpc on colu
A (column 820, He flow 60 ml/min) afforded an analytic 1

sample of 30. Ir (film): 3040, 2930, 2875, 1645,

1320, 1300, 1285, 1265, 1240, 1200, 1175, 1140, 1115,


n fi~









1040, 1000, 990, 920; nmr (CDC 3): 6 2.39 (d with

hitting, J = 7 Hz, 4 H), 3.90 (s, 4 H), 4.84-5.28 (AB m,

minal vinyl H, 4 H) 5.47-6.10 (m, 2 H); mass spectrum

in/e): 154 (M+), 113 (M+ C3H5, major peak).

0 Anal. Calcd for CgH1402: C, 70.10; H, 9.15.
found: C, 70.35; H, 9.11.

paration of cis- and trans-3,4-bis (chloromethyl)-
lopentanone (32

A mixture of 6.75 g (0.0437 mole) of 30 and 12.1

.0440 mole) of iodobenzene dichloride 20a in 75 ml of

oroform was heated at reflux for two hours under a slow

*m of nitrogen. The chloroform solvent was removed by

vaporation affording a slightly colored mixture

ng iodobenzene and crude cis- and trans-7,8-bis

thyl)-1,4-dioxaspiro [4.4] nonane (31). The
atio of 31 was not established although the

reeilinfpmulti'plet centered at 3.65 6 (-CH2C1)

r P ~~ e of a ois-trans mixture. The iodo-
s r moved at 0.25 mm while heating the flask to

istillation of 31 (bp 88-95/0.25 mm)

02 mole, 69%) of 31 possessing a

e use of hydroquinone stabilizer in

m rovedqut did not eliminate decom-

75 g .0300ole) was dissolved
ate ng 200 mg of




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REACTIVITY IN THE TRICYCLO [4.1.0.0^'^] HE PTAN5 YL I DENE AND THE TRICYCLO [5.1.0.0^'^] OCTAN -2 YL I DENE SERIES By OSCAR TRINIDAD GARZA A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FU'.FILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 1975

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UNIVERSITY OF FLORIDA 3 1262 08552 4253

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To MoAy Jam

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ACKNOWLEDGEMENTS The author w shes to express his deepest gratitude to Dr. W.R. Dolbier, Jr., for the patience, encouragement, and guidance which were afforded the author •during his years of doctoral research. Without Dr. Dolbier's timely ideas and suggestions, this work would not have been accomplished. The author wishes lo express his appreciation to the members of his supervisory committee, in particular to Dr. W. Weltner, Jr., for research accomplished with the aid of his experimental group. Further gratitude is extended to Dr. R.W. King for his invaluable varied services which aided the author's research goals on many occasions. A debt of thanks is especially owed to Pat and Jeff Whitehurst who, considering the time allotted, did an excellent job of preparing the rough and final copies ofthisdissertation. Finally, the patience and hard work of the author's wife, Mary Jane, deserve special recognition. Without her support and smiling face, this research could not have succeeded. It is felt that she endured much and deserves a life >)fitting a real lady. 1 1 1

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TABLE OF CONTENTS Page ACKNOWLEDGEMENTS iii LIST OF TABLES V LIST OF FIGURES vi ABSTRACT i x CHAPTERS: I. INTRODUCTION 1 II. SYNTHETIC METHODS 13 III. PYROLYSIS OF p-TOLUEN F SUL FON YLH YDRAZONE SODIUM SALTS 39 IV. DISCUSSION AND CONCLUSIONS 59 V. EXPERIMENTAL 88 APPENDIX 138 REFERENCES 171 BIOGRAPHICAL SKETCH 176 1 V

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LIST OF TABLES Table Page I 26-s + Eu(fod)3. TOO • II 26-a + Eu(fod)3. 100 III Proton Assignments for 26-s and 26-a in the 100 MHz Spectra. 101 IV Reaction Product Yields from si/n-Tri cycl o [4.1.0.02.4] heptan-5-one Tosyl hydrazone Sodium Salt. 119 V Reaction Product Yields from Flow Pyrolysis of sz/n-Tricyclo [4.1.0.02.4] heptan5-one Tosyl hydrazone Sodium Salt. 121 VI Reaction Product Yields from antt-Tri cycl o [4.1.0.02,4] heptaii-5-one Tosyl hydrazone SodiumSalt. 122 VII Reaction Product Yields from synand anti-Tri cyclo [5.1.0.03,5] octan-2-one Tosyl hydrazone Sodium Salts. 123 VIII Volatile Product Yields from Static Pyrolysis of aynand antt-Tri cycl o [4.1.0.02.4] heptan-5-one Tosyl hydrazone Sodium Salts: 140°-^225°. 137

PAGE 7

LIST OF FIGURES Fi gure

PAGE 8

Figure Page A-8 Nmr of antt tri eye 1 o [5.1.0.0^'^] octan2-one tosy 1 hydrazone ( 50-a ) . 146 A-9 Nmr of dimer 52_ obtained from 33-a sodium salt. " 147 A-10 Nmr of dimer 5_2 obtained from 33-s sodium salt. 148 A-11 Nmr of 4-ethyny 1 -cycl opentene (5_5). 149 A-12 TOO MHz nmr of ti-ans 1 -ethynyl -2 -v i nyl cyclopropane ( 54-t ) . 150 A-13 100 MHz nmr of ets 1 -ethyny 1 -2-vi nyl cyclopropane ( 54-c ) . 151 A-14 100 MHz nmr of cyclopropyl region of 54-c . 152 A-15 Nmr of cis 1 -al lyl -2-ethynyl -cycl opropane (i5). 153 A-16 Nmr of octa-1 ,2 ,5 ,7-tetraene (66^). 154 A-17 Ir of s!/n-tricyclo [4.1.0.0^'^] heptan-5one (26-s) . 155 A-18 Ir of antt-tricyclo [4.1.0.0^'^] heptan-5one (26-a) . 156 A-1
PAGE 9

Fie

PAGE 10

Abstract of Dissertation Presented to the Graduate Council of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy REACTIVITY IN THE TRICYCLO [4.1.0.0^'^] HE PTAN5Y L I DE NE AND THE TRICYCLO [5.1.0.0^'^'] OCTAN-2YL I DENE SERIES By Oscar Trinidad Garza August, 1975 Chairman: William R. Dolbier, Jr. Major Department: Chemistry The thermal conversions of the r -tol uenesul f onyl hydrazone sodium salts of (a) the sz/nand anti-tri cycl o [4.1.0,0 '] heptan-5-ones as well as those of (b) the syn3 5 and anti-tricycl [5.1.0.0 '] octan-2-ones were investigated. The chemistry resulting from the generation and sub' sequent reaction of the respective carbenes for each series proved most interesting for the case of the tricyclic heptanyl i denes . Three methods were developed for the required syn2 4 thesis of the synand ant^-tr^cyc^o [4.1.0.0 ' ] heptan-5ones, the first two methods affording nearly equimolar mixtures of the isomeric ketones while the third method afforded a syn-anti mixture in the ratio 2:98. The novel syn tricyclic heptanone proved exceedingly labile in comparison with the anti isomer. ix

PAGE 11

Carbene product distributions for t oth isomers in a giver series proved similar thereby demonstrating that the cyclopropane orientation differences within an isomeric set afforded no readily identifiable differences in reactivity. Although the observed products for each series studied could be explained largely by the established ethylenicacetylenic fragmentation process common to cyclopropyl carbenes, the case for the isomeric tricyclic heptany 1 idenes was subjected to further scrutiny because of the plausible operation of a novel six-electron pericyclic process involving the highly-strained species 1 ,2 , 5-cycl oheptatri ene as the primary product derived from either tricyclic heptanyl i dene. Three C.Hg monomers and one C-,Ho dimer were obtained from the tricyclic heptany 1 i denes while two CoH-,^ monomers o I U were isolated from the tricyclic octanyl ; denes . The novel C^Hg monomer cis -1 -ethyny 1 -2vi ny 1 cyclopropane afforded unusual reactivity, undergoing ostensibly a Cope rearrangement with an approximate half-life, assuming a unimolecular rate-determining step, of two to three hours maximum at 25°C. It remains the subject of ongoing studies, having proved to be the most interesting carbene product isolated from the studies of both tricyclic carbene systems.

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CHAPTER I INTRODUCTION AND BACKGROUND The question of a quasi aromati c structure as a valid picture of the electronic makeup of certain suitablydesigned carbenes has received considerable attention in the past decade. Although cycl opropenyl i dene (]_) has eluded study thus far, cycl opentadi enyl i dene (2^) and cyclo1 2 heptatrienyl idene (3) have been studied in detail. ' 1 2 3 Assignment of structures such as 4^ and 5^ to 2^ and 3^, respectively, has found substantial experimental verifica3 4 tion as the result of work by two research groups ' sup' plemented with extended Huckel calculations performed by 5 Gleiter and Hoffman.

PAGE 13

4 (P^) 5 a(a^) The EHT calculations indicate that the nucleophilic or el ectrophi 1 i c character ought to alternate in the series 1_ 2The nucleophilic character of 1_ and 3, with the o^ singlet of each lower than the u singlet on the potential energy profile, ,vas predicted from calculations of the total charge residing on the respective methylene carbons of ]_ and 3: -0.68 and -0.86. Experii' ntal evidence was in turn provided by W.M. Jones and coworkers in the case of 3_. A Hammett study was performed in which cycloheptatrienyl idene was generated in the presence of an ei qht-to-tenfol d excess of an equimolar mixture of styr^ne and 3or 4-substi tuted styrene. The p value of +1.05 + 0.05 Obtained from this study provided the first quantitative assessment of the nucl eophi 1 i ci ty of a carbocyclic aromati c ca rbene . Cycl oijentadienyl idene , on the other hand, did not readily lend itself to the proposition of el ectrophi 1 icity based strictly on the extended Hlickel treatment. Cyclopentadienyl idene showed a '
PAGE 14

6 7 200° 165' + : c 8 bi shomoaromat i c carbene. In the case of 6^ the vigorous reaction resulting in extrusion of carbon atoms may preclude the existence of a bi shomoaromati c carbene (S^) . Without Hammett studies and suitable trapping reactions employing both electron-rich and electron-poor olefins, which might afford information concerning the 9

PAGE 15

electrophilicity or nucleophilicity of 6^ and 7^, no evidence for bi shomoa''-omati ci ty in 6^ and 1_ would appear to be forthcoming. Even the isolation of stable forms, dimers and/or oligomers, of J_0 and ]_]_, derived from 6^ and 7^, respectively, while perhaps suggesting a special intermediate as their precursor, would not demonstrate bi shomoaromatici ty as an operative force in these systems. 10 n The discussion of bi shomo aroma ti ci ty in the case of 2» fortunately, can be extended due to the supportive work performed by Bergman and Rajadhyaksha included in 1 the same paper. Treatment of 3-bromo-bi cycl o [3.2.1] octa-2 ,6-diene [Yl) with potassium t-butoxide in DMSO at 25° afforded 8 in 29% yield. Further work demonstrated that (a) carbon-halogen bond cleavage occurred in the

PAGE 16

rate-determining step of the reaction, and (b) rapid, reversible deprotonation-reprotonati on of T_2 occurred at a rate greater than that of rearrangement. The scheme postulated by Bergman en vi si oned a homocon j ugated anion (13) t-Buo -* t-BuOH 12 8 13 1 14 giving way to a homoconj ugated neutral intermediate ( 1 4) which subsequently underwent cleavage in the manner typical of cycl opropyl carbenes . Since 7_ and }3_ both afforded identical product (8), it was logical that a common intermediate (1_4) should be invoked, the final result being the pictorial representation (15) which corresponds to the p configuration of the singlet carbene. In summary

PAGE 17

it can be stated that the isolation of 8 via generation of 7 from the tosyl hydrazone sodium salt does not appear to be 15(pM merely a simple case of a cycl opropyl carbene undergoing the 1 2 wel 1 -documented ethyl ene-acetyl ene fragmentation process ' but is, in fact, a case of a stabilized carbene giving said product (8). Although further argument concerning the mechanistic origin of 8 may prove ethereal, it is conceivable that 8 could also arise from allene (11) by a Cope process n 11 8

PAGE 18

Consideration of the 1,3-bishoniocyclopentadienide species (J_6) , of which J_5 would be the o cation, allows further insight into the postulated existence of J_5_. HMO calculations predict appreciable bonding interactions be1 2 tween the allylic anionic and olefinic systems in 1 6 . The resonance integral 6^^ (or & ac) is approximately equal to 0.3 3„ where 3 is assigned a value of 18 kcal/mole, 1 3 a value normally used for benzenoid systems. Charge 16 17 18 density is greatest at C-2 and C-4 (0.426), considerably less at C-6 and C-7 (0.064), and least at C-3 (0.021). Interestingly enough, the tetracyclic hydrocarbon (18) is obtained as one of three products upon equilibration of J!_7 employing Strei tweiser ' s catalyst-solvent system, CsNHCgH^^ in CgH^^NH^.^^ In order to further test the hypothesis of bishomO' aromaticity in the realm of carbene chemistry, it was

PAGE 19

10 deemed necessary to investigate this question from the viewpoint of bishomocycl opentadienyl i dene , a species which could possess two isomeric forms; i.e., syn and anti configurations of the fused cyclopropane rings should be possible. The bi shomocycl opentadi enyl i denes , 3z/nand 2 4 anti-tricyclo [4.1.0.0 ' ] hep tan5-y i i denes , 19-s and 1 9-a devoid of the molecular constraints as encountered in 19-s 19-a 6^ and 7^, would be capable of generating the novel cyclic allene 1 , 2 , 5-cycl oheptatri ene ( 2_0) , whose structural deformation would place it in the same class with the known 1 ,2-cycloheptadiene {ZV) and 1 , 2-cycl ohexadiene {Z2) species. ' Mononiers 21 and 22 have been shown to be 21 a, 22

PAGE 20

11 transient intermediates as evidenced by the isolation of their dimeric and tetrameric products. In the case of 22_ the monomer has also been trapped employing both styrene and 1 ,3-diphenyl-benzo [c]-f uran J ^^ '^ The observation of possible dimeric and/or tetrameric products resulting from 20. would lend credence to the concept of a bi shomoaromati c carbene although such an observation, by itself, constitutes a unique multiple-bond fragmentation process for a new carbene rather than the actual generation of a particular pseudo-7T stabilized carbene. Other interesting features of the bi shomocycl opentadienyl idene investigation would lie in the isolation of the monomeric species, e^s-l -ethynyl -2-vi nyl -cycl opropane (23) and tetracyclo [4 .1 .0 .0^ '^0"^ '^] heptane (24). The cyclopropane (2_3) presents an interesting problem since it might possibly arise from 20^ via a Cope process or simply originate as the primary product from the ethylene-acetyl ene fragmentation process common to cyclopropylcarbenes. Superimposed on the mechanistic alternatives would be the questions of the inherent stability and reactivity of the unknown 2^. Tetracyclic heptane (24), synthesized and pyrolyzed by Christl and Bruntrup, converted to cycloheptatriene at 150°C with a rea tion halflife of ca. five hours. Despite a strain energy of approximately 100 kcal/mole, it appears that Z± is thermally stable.

PAGE 21

12 suggesting that suitably-generated 19-s or 19-a might give rise to 24 via C-H insertion. 23 (=54c) 24 Further speculation about the reactivity of 1 9-s and 19-a only served to increase the demand for the actual experimental work. The work described in this dissertation was performed principally on the synand ant-itri cycl o [4.1.0.0^'^] heptan-5-yl idenes in order to determine the basic reactivity of these systems and thereby add to the discussion of homoaromatici ty in alicyclic carbenes. Further elaboration of the working hypothesis was provided by inspection of the eynand antitri cycl o [5.1.0.0 ' ] octan-2-ylidenes, 2 5^s and 2 5a. which provided a severe test for operational homoaromati ci ty in cariene systems possessing favorable geometries.

PAGE 22

CHAPTER II SYNTHETIC METHODS Synthetic entry into both the tricyclo [4.1.0.0 '] heptan-5-yl idene and the tricyclo [5.1.0.0 '] octan-2ylidene series was provided by the synthesis of the corresponding syn and anti ketones for each series. Conversion of the ketones to the corresponding p-tol uenesul fonyl hydrazones ( tosyl hydrazones ) was desirous since tosyl hydrazone lithium, sodium, or potassium salts are normally stable precursors which can be subseijuently pyrolyzed or photolyzed in solution ' or pyrolyzed in the solid state a la Schecter. Three synthetic methods were developed for the synthesis of si/nand an/ ttricycl o [4.1.0.0 '] heptan-5-ones , 26-s and 26 -a . respectively. The first two methods (methods A and B) both afforded a nearly even mixture of t\,e ayn and anti ketones while the third method (method C) afforded the ketones in a syn-anti ratio of 2:98. Method A (Scheme I) began with the known conversion of isobutyric acid to the corresponding acid chloride followed by treatment with tri ethyl ami ne to afford the dimethylketene dimer, tetramethyl 1 , 3-cycl obutanedi one (27) . Treatment of 2_7, in the known manner, with allyl Grignard 13

PAGE 23

14 afforded the C-,4 keto-al cohol , 5-al lyl -5-hydroxy-2 ,4 ,4trimethy1-7-octen-3-one (28), which was subsequently converted to diallyl ketone (21) by base-catalyzed cleavage with barium hydroxideJ^ Diallyl ketone (29) was converted to its ethylene ketal (30) which was treated with iodobenzene di chl ori de . ^°^ ''^ The crude mixture of ai sar\6 trans7,8-bis (chloromethyl )-l ,4-dioxaspiro [4.4] nonanes (31), the product of addition of one mole of chlorine concomitant with radical cyclization to generate the f i ve-membered carbocyclic structure, was subjected to acid-catalyzed hydrolysis resulting in restoration of the ketone moiety. The resulting mixture of eisand trans3 ,4-bi s (chloromethyl)cyclopentanones (12) was treated with 50% sodium hydroxide whereby an a, y loss of two moles of HCl was effected resulting in the isolation of two ketonic products which nmr, ir, uv, mass spectral, and elemental analyses indicated to be CyHgO isomers. The isolation of the two ketonic products, which proved to be the desired tricyclic heptanones, 26-s and 26-a . proved initially troublesome when attempting the separation work employing typical glpc methods. An injection of the isomeric mixture of ketones onto various Carbowax 20 M columns (column temperatures: 130°C-160°C) typically resulted in the isolation of three isomeric ketones: (a) antt-tricyclo [4.1.0.0^'^] heptan-5-one , (b) 3,5cycloheptadienone, and (c) 2 ,4-cy^l oheptadienone . The

PAGE 24

Scheme I S0C1 (CH3) CHCO^H 15 NEt' / / 27 1) CH^ CH-CH^MgBr 2) NH^Cl (CHJ CH J 2 C C(CH,) II o 28 Ba(OH) (CH20H)2 © CH2CI cMCI CHCl CH2C1 H© 'U" H2O, EtOH 30 31 CH^Cl CH^Cl 50% NaOH steam di s . sijn'.anti 52:48 32 26-a 26-s

PAGE 25

Scheme I continued 26-a 16 26-s a. N-NH-Tos N-NH-Tos Na® Tos N N Na N Tos © 34-a 34-s

PAGE 26

17 anti-tricycMc ketone was identified by comparison of its nmr (100 MHz) with that reported by Gajewski and Shih (1970). The outstanding feature of the nmr of 26-a is the unsymmetri cal quartet (J = 3.5 Hz) with a two-proton integration at 6 0.85. The remainder of the nmr spectrum showed three multiplets of two-proton integration each located at 6 1.25, 1.56, and 2.08. The ir (1720 cm"^), 'J^ ('^imv '^37 "f^' ^ 28), and mass spectrum (M 108) were III G A also confirmative of the anti isomer; howev^jr, elemental analysis did not po.e satisfactory, a situation which persisted until the glpc methods were rectified. The 2,4 and 3,5-cyclcheptadienones, recognizable due to (a) the four-proton multiplet in the region 6 2.172.83 for the 2,4 isomer and (b) the four-proton doublet (J = 5.8 Hz) cefitered at 6 3.00 for the 3,5 isomer, were accounted for by an acid-promoted rearrangement which destroyed the entire fraction of the s/;ntr i cycl i c ketone (26-S ) and only a portion of the anti fraction ( 26a ) . Previous work by Borg and Kloosterziel had shown that the cycl oheptadi enones were interconvertible in the temperature range 60°-100° via a facile 1,5 hydrogen shift, resulting 22 in an equilibi'ium mixture dominated by the 2,4 isomer. This equilibrium explained the observation that the cycloheptadienones eluted from the glpc column as a mixture (two overlapping peaks) while residual 26-a eluted as a distinct component.

PAGE 27

18 © Isolation of analytically pure syn-and aTiti-tri cycl i c heptanones was accomplished by the use of an alkaline column {]0% Carbowax 20 M) employing 3.5% potassium hydroxide to effectively remove active sites from the inert sui^port, typically Chromasorb P-Regular. Whereas liberal injections of ammonia vapor had not prevented destruction of the ketones in the initial glpc work, the potassium hydroxidecoated column allowed for almost quantitative (95% with cycloheptanone as internal standard) separation and isolation of 2f:-:_s_ and 26-3 in the temperature range 130°-165°C. It was noted, however, that column temperatures in the range 185°-196° led jgain to the almost complete destruction of 26-s (4% reco/ery) suggesting that perhaps the sijn isomer v,as thermally labile. The novel szyntricycl o [4.1.0.0^^^] heptanone ( 26-s ) afforded four complex multiplets in its 100 MHz nmr spectrum, each multiplet of two-proton magnitude. The multiplets were located at 5 0.76, 1.50, 1.78. and 2.18.

PAGE 28

19 The multiplets at 1.50 and 1.78 were overlapping, a featute which readily distinguishes 26-s from 26-a . The ir (1700 cm' ), uv (A ^„ 283, e 70), and mass spectrum (M 108) also m a X confirmed the structure of this C^HnU ketone isomer. Elemental analysis of 26-s proved satisfactory. Silica gel chromatography conveniently afforded separation of 26-s and 26-a of sufficient purity to allow for subsequent conversion to the corresponding tosylhydrazones, 33-s and 33-a , respectively. Whereas 33-s was observed to have been formed in 83% yield, 33-a , unfortunately, was obtained in only 31% yield. Conversion of 33-s and 33-a to the corresponding sodium salts, 34-s and 34-a , was quantitatively achieved employing sodium hydride (1.2 equivalents) with tetrahydrof uran solvent. Potassium salts of 33-s and 33-a were made by treatment of the tosylhydrazones with potassium tert -butoxi de , again using tetrahydrofuran solvent. Method B (Scheme II) employed a synthetic sequence which appeared to be a more convenient synthetic route than method A. Drawing on the analogy provided by workers such 23 24 as Doering and Gutsche in performing intramolecular trapping of intermediates of the copperketocarbene type by a remote double bond, a sequence o1 steps was devised which would utilize cis-ethyl 2vi ny 1 -cycl opropanecarboxylate ( 35-c ) as the point of entry into the synthetic sequence. Although no stereospecific synthesis of 35-c has

PAGE 29

Scheme II 20 no° + N2CHC02Et KOH H^O-MeOH CO2H S0C12 C-Cl CH2N2 Et20 36 37 C-CHI CuSO 26-a 26-s a. syn :anti 47:53

PAGE 30

21 been reported to date, a ^-c venient synthesis of aisand trans-ethyl -2vi nyl -cycl opropanecarboxyl ates (3^) was 25 supplied by Vogel and coworkers. The oistrans ratio of 35 was determined to be 40:60. Saponification of cisand trans-35^ afforded the corresponding mixture of ois-and trans-cycl opropanecarboxyl ic acids ( 3j5) . Treatment of 3_6 .with thionyl chloride afforded a 38:62 mixture of the ci-sand trans-cycl opropanecarbony 1 chlorides (2Z) • Up to this point the synthetic work was essentially a duplication of Vogel 's work which had been concerned with the synthesis and reactivity ctsand trans-2vi ny 1 -cycl opropyl i socya25 nates. Treatment of 37^ with ethereal diazomethane afforded a crude mixture of ctsand trans-1 -di azomethyl keto2-vi nyl -cycl opropanes (3^) as evidenced by t.:e strong ir band at 2100 cm" and the diazomethyl singlet at 6 5.31 in the nmr. Copper-catalyzed decomposition of _38 in refluxing cyclohexane afforded the desired isomeric tricyclic heptanones, 2.6 -s and 26-:a . in the sijn-anti ratio of 47:53; the yield was 32% based upon the ais acid chloride ( 37) . Method C, while not providing a satisfactory synthesis for 26-s , did provide an interesting route to 26-a . The starting point for the synthetic sequence, as outlined in Scheme III, began with bicyclo [3.1.0] hexan-2-one (39) which could be conveniently synthesized from either 4tosyl oxycycl ohexanone or 2-cycl opentenone .

PAGE 31

Scheme 1 1 1 22 39 a, 3% H^SO^ Br, (CH^OH) 42 40 © (CHJ SO I NaOMe DMSO NaH DMSO 41 26-a Si/n :anti 2:98 Initially employing the basic procedure for the synthesis of bicycle [3.1.0] hex-3-en-2-one {A2) outlined 2 8 by Russel and Stevenson, conversion of 3_9 to the crude bromoketal (4_g) was accomplished only after allowing the bromination to proceed at 25°-38"C in ethylene glycol instead of at 0°. Further modification of the basic procedure was found necessary in the subsequent step for which reverse addition (pinchwise addition of sodium methoxide to a DMSO solution of 4^) appeared to be a necessary condition for obtaining a respectable yield, 29% from 39, of the ethylene ketal (^L) of bicyclo [3.1.0] hex-3-en-2-one (42). Deketal ization of 41 was accomplished with 3%

PAGE 32

23 HpSO, affording 42^ in 58% yield. Subsequent treatment of 42 with trimethyl s u1 f oxoni urn ylide afforded 26-a and 26-s in 66% yield; however, the syn-anti ratio proved to be 2:98, a result which was not totally unexpected. The synthesis of 42^, a monohomocycl opentadienone , catalyzed an attempt at the preparation of the correspond.ing tosyl hydrazone from which the carbene of 42^ could ultimately be generated. The attempt met with failure because ptosyl hydrazi ne destroyed the carbon-carbon double bond in Michael addition fashion. This result agreed with similar results reported by Kirmse who observed that various cyclopentenones and cycl ohexenones underwent addition as well 29 as condensation in reactions with ptosyl hydrazi ne . 3 5 The synthesis of syn and anti tricyclo [5.1.0.0 ' ] octan-2-ones , 49-s and 49-a , outlined in Scheme IV, represents the synthetic sequence developed by Lambert, Koeng, 30 and Hamersa. Although Lambert had removed a substantial fraction of the ois, cis-tricyclo [5,1.0.0 ' ] octyl-2carboxylic acid (46^) from the mixture of cis , ais and ais , trans acids (46^) by fractional crystallization, no attempt was made in this work to separate isomeric tricyclic octyl species until arrival at the ketone stage. Birch reduction of benzoic acid afforded 1 ,4-di hydrobenzoi c acid (43) which was treated with ethereal d iazoniethanu . Methyl1 ,4-di hydrobenzoate (44), product of methylation with

PAGE 33

Scheme IV 24 o Na/NH3 EtOH CO^H 43 CH2N2 Et20 C02Me 44 CH^l^ Zn Cu (3 runs ) CO^Me 10% NaOH > Pb{OAc) C3)(S) 45 46 OAc 47 LiA1H4 Et20 48 CrO. H2SO4-H2O CH^CCH^

PAGE 34

Scheme IV continued 25 TosNHNH EtOH syn :anti 77:23 TosNHNH, EtOH N-NH-Tos N-NH Tos Tos-N-N Na N-N-Tos Na 51-a 51-s

PAGE 35

26 di azomethane , was eye 1 opropan > ted twice by three-fold treatment with methylene iodide and a zinc-copper couple. The product mixture, largely ois , ois and ais ^ trans-methyl 3 ^ tricyclo [5.1.0.0 '^] octyl -2-carboxy 1 ates (4_5) , was converted to the corresponding mixture of acids (4i6) with 10% sodium hydroxide solution. Decarboxylation of 46^ with lead tetraacetate afforded the isomeric tricyclic octyl acetates (47 ) which were subsequently reduced with lithium aluminum hydride to a crude mixture of the alcohols (£8). Oxidation of 4_8 with the Jones reagent provided the tricyclic octanones 49-s and 49-a , which were separated and purified by four consecutive short-path distillations. The syn-anti ratio of the ketones was determined to be 77:23 from this sequence. Conversion of 49-s and 49-a to the corresponding tosyl hydrazones was accomplished although the yields were not good, s-yn-tricycl o [5.1.0.0^'^] octan-2-one tosylhydrazone ( 50-s ) was obtained in 42% yield while the ant-i tosyl hydrazone (50-a) was obtained in only 34% yield. Subsequent conversion of 50-s and 50-a to the sodium salts, 51 -s and 51 -a , was accomplished in the manner identical to that of the tricyclic heptanone tosyl hydrazones , 33-s and 33-a . The concludinu facet of work connected with synthetic methods deri es f i om an attempt to assign the various proton absorptions in both the 60 and 100 MHz of the

PAGE 36

27 tricyclic heptanones 26-s and 26-a . Employing Eu (fod)^, tris (1 ,1 ,1 ,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedione) Europium (III), 1 anthanidei nduced shifts produced some rather interesting spectral changes, the most interesting of which demonstrated that the two protons adjacent to the carbonyl function (a-methine cyclopropyl protons) in both 26-s and 26-a were not located farthest downfield in the normal nmr spectra. It appeared that the protons most deshielded in these systems were the two protons located at C-1 and C-2, the 3-methine cyclopropyl protons. Further, 3 1 a c rough calculations of the agreement factor R for the four types of protons present afforded values of 0.16 and 0.23 for systems 26s and 26-a , respectively. It was also of interest to note that endo protons at C-3 and C-7 in 26-a lay 0.65 ppm farther upfield than the endo protons of 26-s . It appeared that in 26-a the opposing banana bonds of the cyclopropane rings were exerting a shielding effect on the opposing endo protons while the geometry of 26-s excluded this effect. These nmr obser'Vu ti ons of 26-s and 26-a brought to mind the case of bicyclo [3.1.0] hex-3-en-2-one (42^) where nmr work by Hasty has shown that the a-methine cyclopropyl proton absorbed at 6 2.01 and the g-methine cyclopropyl 32 proton at 2.38. Further, the C-6-endo proton, as might be suspected, absorbed at higher field (1.12) than the exo proton (1.32) due to the shielding influence of the pi cloud

PAGE 37

28 endo 42 42-r of the suitably disposed double bond. Since (42^) has a resonance form ( 42-r ) which places a positive charge adjacent to the 3-niethine proton, it may be unfair to use (42) as a model for analogy with regard to 26-s and 26-a . Nevertheless, the observed effects in the nmr of 26-s and 26-a serve to create speculation about the possible contribution 26-aa -K>X/V/N ^ 26 AA/vy^^»26-r of a species which possesses finite partial charge separation as in 26-r . The extreme case, of course, would be 21 contribution from the anti -homoaromati c species 26-aa . The nmr spectra on the following pages demonstrate the "leap-frog" effects which occurred upon the addition of Eu(fod)3 to either 26-s or 26-a .

PAGE 38

29 2 I 1X1 CM o I c ft) 4-> O. CvJ o I s to E C N O s-i-§-«-§-»-

PAGE 39

30 CO o o (O 10 I CO •o o 3 cn

PAGE 40

31 CM •M i. i~ to I CO X) o E L.

PAGE 41

32 CO i. I/) I vo t^ o o o S

PAGE 42

33 o 4-> to i. I OsJ <>0 o S in u

PAGE 43

34 I c: o I un I c +J Q. O) CM O >> •I— •-> I S' sE c o U3 «D (U 01

PAGE 44

35 o o o 10 I CM CO -a o IL§_8_2_a_8

PAGE 45

36 o CM O O I CM CO XJ O E CO 01

PAGE 46

37 o o O <0 I CM cn o e 7S (U u 3 -8-8-2-^8

PAGE 47

38 o 4J i. i. re I oo X) o UJ o 01 irs g_§_g_a_8

PAGE 48

CHAPTER III PYROLYSIS OF p-TOLUENESULFONYLHYDRAZONE SODIUM SALTS Simple speculation concerning the probable products 2 4 to be obtained from both the tricyclo [4.1.0.0 ' ] heptan-5' 3 5 ylidenes and the tricyclo [5.1.0.0 ' ] octan-2-yl i denes led to the conclusion that moderately volatile products were distinct possibilities. With this in mind it was concluded that pyrolytic techniques which avoided solution work and hence separation problems would be preferred. The method of choice appeared to be hiqh-vacuum pyiolysis of the neat salts. The sodium salts were, for the most part, pyrolyzed according to one of thr^-e si'lected procedures. The foremost technique, an extrapolation of the static technique 17 33 commonly employed by workers such as Schecter, ' was designated the drop-static (D-S) technique in which controlled dropping of the sodium salt onto a heated glass surface under high vacuum (7 x 10' 3 x 10' mm) was accomplished employing virtually a one-piece vacuum unit (Figure 11), which allowed for pyrolysis, trapping, and transferral (of products) in an all-in-one type of operation. The second technique was the flow (£) technique, 39

PAGE 49

40 s in I/) >i O Q. E :3 O > en en I Q ®€:^

PAGE 50

41 commcniy referred to as the "hot tube" technique. This technique, in comparison wi', h the D-^ technique, allowed for longer contact times thereby increasing the chances for further rearrangement of i ni ti al lyformed carbene products. The final technique was simply the infrequently-used static (S^) technique which did find one important application resulting in the isolation of an elusive compound ( 54c ) . The only solution work performed involved several trapping 2 4t reactions involving the sj/n-tricyclo [4.1.0.0 ' J heptan-5ylidene species a id styrene or dim^^thyl maleate. The majority of pyrolysis work, involving the sodium salts 34-s , 34-a , 51 -s and 51 -a , was performed on 34-s and 34-a . Although it was hoped that the different disposition of cyclopropane rings might serve to alter the product chemistry in going from the syn to the anti carbene in each series, this did not prove to be the case. In fact, it appeared tliat the syn-anti reactivity for each series was the same. Drop-static ( D-S ) and simple static (S) pyrolyses of 34-s and 34-a in the range 160°-500"C afforded a white, waxy material, melting sharply at 46°-47'\ which ras conveniently trapped out on the cold finger (O^-IO") of the modified sublimators used in the D-S and S^ pyrolyses. The waxy solid exhibited a penetrating odor which always served to announce its presence in the pytolysate. The solid

PAGE 51

42 discolored upon exposure to air, assuming a yellow-brown coloration within one hour. The thermal stability of the solid appeared suspect since attempted sublimation under high vacuum of impure material led to tarring. Heating the solid in benzene or toluene at temperatures > 50° even under argon or nitrogen also had a deleterious effect. The structure of the solid was established by spectroscopic evidence and analysis. Infrared bands at 3020, 1550, and 650 cm' indicated the necessary double bond feature. The nmr spectrum, perhaps the most confirmative piece of spectroscopic evidence, showed a four-proton multipiet at 6 2.33, a two-proton multiplet at 2.35-2.90, a four-proton multiplet at 3.02, and a six-proton multiplet at 5.55. The two-proton multiplet was overlapped on each end by the adjacent four-proton multiplets. The uv spectrum showed a X^^^ at 254 (e 8120). The uv absorption maximum corresponded rather well with that reported for tricyclo [9.7.0.0 ' ] octadeca-5,9,n ,15-tetraene (51).^^ Mass spectral analysis showed the parent peak to be m/e 184. Elemental analysis proved satisfactory for a C,.H,^ ole14 ID finic hydorcarbon. The structure therefore assigned to this unique product was tricyclo [7.5.0.0^'^] tetradeca4,7,9,12-tetraene (52).

PAGE 52

43 max e 254 8120 52 = 252 max e = 8600 53 a. Hydrogenati on of 52^ resulted in the uptake of four moles of hydrogen, the hydrogenated product clearly possessing the parent peak of m/e 192. Attempts to form DielsAdler adducts with maleic anhydride, dimethyl acetylenedi carboxyl ate , and tetracyanoethyl ene failed, resulting in the tarring of dimeric 5_2. This failure to form a suitable Diels-Alder adduct was disappointing due to the effort spent in trying to achieve the desired result; nevertheless, it may \/ery well be distortions of the molecular framework in the vicinity of the butadiene moiety are prohibiting the 2+4 cycl oaddi tion. An interesting facet of the isolation and characterization work of 5^, formally the dimer of 1,2,5-cycloheptatriene (^) , is that the dimer is the major product under all pyrolytic conditions, irregardless of technique and temperature. In light of this fact, the monomeric species 2_0 would deserve consideration as the primary product resulting from collapse of both tricyclic heptanyli denes via a unique six-electron pericyclic reaction ( vide i nf ra ) .

PAGE 53

44 Volatile products isolated from the D-S and S^ pyrolyses of 34-s and 34-a included toluene (1.7), cycloh^ptatriene (_56), and two much Mure interesting products, trans-ethynyl -2-vinyl-cyclopropane ( 54-t ) and 4-ethynylcyclopentene (^B). Glpc analysis employing a column temperature of 68^-70"C provided analytical samples of 54-t ^ ^ and 5_5. Tl; :yclopropane was isolated in ] .0-^^ .8% yi Ids in the temperature range 160°-400° with the cyclopentene appearing on'y at 500° in 3.8% yield. Comparision of the nmr spectrum of the crude volatile pyrolysate prior to glpc with the nmr spectrum of purified 54-t on several occasions indicated that certain peaks in the cyclopropyl and vinyl regions of the nmr spectrum of the pyrolysate were missing in the nmr of purified 54-t . This observation led to the conjecture that u'lder the glpc conditions the eis-1 -ethynyl • 2-vinyl -cycl opropane (54-c ) , if present in the pyrolysate.

PAGE 54

45 was being destroyed. In fact, until the actual isolation of 54-c , the assignment of trans sterochemi s try to the gl pc-puri f i ed cyclopropane hinged upon this observation as well as the known instability of both eis-l ,2-di vi nyl or "DC cyclopropane (6_8) and c?is-l , 2-diethynyl -cycl opropane (69 ) . The ir spectrum of 54-t showed the necessary monosubstituted-acetylene bands at 3320 and 2120 cm" with the vinyl absorptions displayed at 1635, 980, and 905 cm" . The 100 MHz nmr spectrum at high field showed a threeproton mulitplet at 6 0.80-1.40 (Hg, H-,, and Hg), an acetylenic doublet at 1.85 (Hr), and an allylic multiplet at 1.58-1.94 (H,). The olefinic regions displayed an ABX pattern with multiplets centered at 4.96 (H^). 5.12 (H^), and 5.40 (H,). Coupling constants afforded by first order analysis are given below: 1.2 1,3 1,4 '2,3 5,6 16.8 Hz 9.5 7.5 2.5 2.0 54-t

PAGE 55

46 Mass spectral analysis of 54-t demonstrated the parent peak to be m/e 92, the parent peak also being the base peak. Elemental analysis in turn proved satisfactory for the C^Ho olefinic hydrocarbon. The assignment of the 4-ethynyl -cycl opentene (55) structure resulted from comparisons with the reported speC' troscopic data of 5_5 which was isolated by Cristl and Harrington as the major product from the pyrolysis of nor37 tricyclenone p-tosylhydrazone sodium salt (^) . The ir spectrum of 5_5_ displayed bands at 3325 and 2125 cm , in58 160' dicative of a monosubsti tuted acetylene. The cis nature of the carbon-carbon double bond was supplied by peaks at 1620 and 690 cm" . The 60 MHz nmr spectrum showed an acetylenic doublet at 6 2.04, a five-proton multiplet region at 2.203.20, and an olefinic singlet of two-proton magnitude at 5.68. Mass spectral analysis showed the parent peak, also

PAGE 56

47 the base peak, to be m/e 92. Elemental analysis proved satisfactory thereby confirming the structure of 5^. It should be noted tiiat flow (F) pyrolytic work led to increased yields (6.9-25.9%) of 55 in comparision with D-S work . The fourth and final true carbene product, discounting cycloheptatriene and toluene as bona fide carbene products, to be isolated from pyrolyses of 34-s and 34-a was crs -1 -ethynyl -2-vi nyl -cycl opropane ( 5 4-c ) in 17-23% yield. This elusive compound was successfully generated by a simple modification of the basic static technique. Maintaining the sublimator cold finger at -72 to -65°C, twice the normal amount of given sodium salt usually employed was heated from an initial temperature of 140° to 225° over a period of thirty minutes. For the first time, the diazo precursor, 2 4 sz/n-or an tt-5-diazo-tricyclo [4.1.0.0 ' ] heptane (5£) was observed to have been conveniently generated and trapped (on the cold finger). Coinciding with the observation of the red diazo compound was the successful isolation of 54-c , a species of unusual reactivity. Whereas 54-t proved thermally stable at Isg^C in deuterochl orof orm solution, 54-c underwent complete rearrangement within thirty-six hours in deuterochl oroform solution at 25° to afford 52^. The implications of this rearrangement upon the nature of the primary product obtained from collapse of the carbene to product are considerable. At this poin', although no hard kinetic

PAGE 57

48 evidence is yet available, it appears thai. 54-c has a halflife in solution of perhaps two to threp hours maximum, assuming the unimol ecul ar process, 54-c— ^2( , to be rate determining. The si/nand antt-5-diazotri cycl o [4.1.0.0 ] heptanes (5_9) proved extremeiy unstable, appearing to yery slowly lose nitrogen even at the low temperatures employed. This was not surprising since secondary aliphatic diazo compcijnds had generally betn demonstrated to not survive the pyrolysis conditions w ei generated from the corresponding p-tosylhydrazone salts. Moreover, the instability of 59 was in accordance with the reported instability of dicyclopropyldiazomethane (6_0) which must be kept below -30°C in order to sufficiently retard decomposition.'^ 59 60

PAGE 58

49 The ir spectrum of 54-c showed diagnostic absorptions at 3310, 3085, 2120, 1635, and 985 cm"^ although interference from cycl oheptatri ene and dimer 52^ tended to obscure absorptions elsewhere in the spectrum. The 100 MHz nmr spectrum at high field showed two one-proton multiplets * at 5 0.78 (Hg) and 1.20 (H^). A two-proton multiplet region was observed at 1.48-1.84 (H. and Hg ) for the aUylic and propargyl protons followed by an acetylenic doublet (He) at 1.88. The olefinic regions displayed an ABX pattern with mulitplets centered at 5.10 (H^), 5.24 (H2). and 5.64 (H^). Coupling constants are given below: 1,2 '1,3 1,4 2,3 5,6 15.8 Hz 8.5 Hz 7.5 Hz 2.5 Hz 2.0 Hz 54-t Suitable model compounds for nmr analysis of both 54-t and 54-c as well as 65^ were provided by vinyland ethynyl -cyclopropane . 39a, b

PAGE 59

50 In an initial attempt to trap the key reactive intermediat'5, 1 , 2 , 5-cyc1 oheptatr-j ene (2^), pyrolysis of 34-s via the D-S technique was effected under high vacuum (9 x 10' mm: maximum pressure reading) employing a matrix isolation unit, with the matrix window maintained at 6°K as the pyrolysate trap.* Inspection of the uv-visible range 200-500 nm showed the only readily discernible absorption to be due to 5i^2, A 254. Ir inspection showed principally the presence of the cyclopropane 5^ and dimer 5J^. A peak at 2040 cm" with a shoulder at 2035 cm" was of primary interest althougii without considerably more work in this area it would be extremely premature to assign the absorption to a high-energy allenic stretching mode which would probably be characteristic of 20. Several attempts to trap the monomer 2_0 with styrene and dimethyl maleate failed. The products obtained from these reactions were the spiro edducts resulting from trapping of the carbene itself. Heating 34-s in the presence of either styrene or dimethyl maleate in tetraglyme solution afforded the respective adducts 2-phenyT-spi ro ? 4 [cyclopropane-1 ,5 ' -s7/n-tricyclo [4.1.0.0 ' ] heptane] (61 ) and trans-2 ,3-di carbomothoxy-spi ro [cycl opropane-1 , 5 ' syntricyclo [4.1.0.0^'^] heptane] (62). Although the yields Lowtemperature matrix isolation experiments were made possible by the use of matrix isolation equipment avail able in the laboratories of Dr. William Weltner, Professor of Chemistry, at the University of Florida.

PAGE 60

51 61 'V Me02C 62 C02Me of 6J_ (34%) and 6^ (39%) were not spectacular, they were nevertheless sufficient so as to allow characterization of both species. The mass spectrum of 6_1_ showed the parent peak to be m/e 196 with elemental analysis proving satisfactory for the C,cH,g behzenoid hydrocarbon. Peaks at 3070, 3040, 1605 and 700 cm" indicated the presence of a monosubsti tuted mononuclear aromatic structure while an absorption at 3010 cm" indicated the cyclopropane structural feature. The nmr of 6J_ proved most informative since a set of overlapping triplets situated at 6 2.15 and 2,30 provided evidence for the presence of an isomeric mixture consisting of aisj cis-6J_ and tranc, trans S^ . The 60 MHz nmr of isomeric 6J_ c ,c-61 t,t-61

PAGE 61

52 showed two four-proton multiplet regions at 6 -0.05 0.73 and 0.75 1.93. The spire cyclopropane hydrogens gave rise to (a) one distinguishable doublet at 1.25 and (b) the set of overlapping triplets previously mentioned. The highfield triplet had a coupling constant of 7.5 Hz while the low-field triplet possessed a coupling constant close to 7.0 Hz in magnitude. The uv spectrum displayed B-bands at 262, 267, and 276 nm with a much more intense K-band at 226 nm (e 7490). The K-band, while 22 nm higher than that of benzene was reasonable since cycl opropyl benzene itself shows a K-band at 219 nm ( e 8900).^° The assignment of trans stereochemistry to the spiro dicarboxylate ^2 was based on the size of the coupling constant obtained from the AB quartet generated by the spiro cyclopropane hydrogens in the 60 MHz nmr spectrum. The 5.8 Hz splitting observed corresponded well with the 5.6 Hz splitting reported for dimethyl -3, 3-dimethyl cycl opropanetrane-l ,2-dicarboxylate (63). Further the cis and trans cyclopropane dicarboxyl ates 64-c and 64-t have respective H-,C CHo CO^Me CO2CH3 H C02Me MeO^C C02Me 63 64-c 64-t a-

PAGE 62

53 J. 's of 8.8 and 6.6 Hz, again confirming the trans stereo42 chemistry of spiro adduct 6_2. The 60 MHz nmr of 6^ displayed two four-proton multiplets at 6 0.52 and 1.70, the two-proton AB quartet with doublets located at 2.42 and 2.65, and two three-proton singlets at 3.72 and 3.76. The mass spectrum showed a very weak parent peak (< 1%) but the base •peak at m/e 117, corresponding to CgHg , demonstrated the facile loss of formally two carbomethoxy radicals and one hydrogen atom. The ir spectrum showed particularly strong absorptions at 1740, 1440, 1340, 1290, 1230, and 1165 cm~\ 3 5 Pyrolyses of sz/nand anti-tricycl o [5.1.0.0 ' ] octan2-one tosyl hydrazone sodium salts, employing the D-S technique, afforded two products in variable total yields ranging from a high of 79.9% to a low of 26.5%. The range of temperatures examined was from 260° to 400°C with product inversion occurring in the vicinity of 400°. The primary product was determined to be ciii -1 -allyl -2-ethynyl -cycl opropane (6_5) with the 1,5 hydrogen-shifted derivative, octa-1 ,2,5,7-tetraene (^6), growing in yield with corresponding increase in pyrolysis temperature. The 60 MHz nmr of 6_5 showed a one-proton multiplet at 6 0.47 (Hg), a complex twu-proton multiplet at 1.02 (H_ and H^.), and a complex one-proton multiplet at 1.38 (Hg). An acetylenic doublet was displayed at 1.81 (H^) followed by a two-proton allylic multiplet at 2.23 (H,).

PAGE 63

54 The vinyl protons gave rise to an ABX pattern with multiplets centered at 5.02 (H^), 5.10 (H^), and 5.95 (H^). Simple first-order analysis supplied the relevant coupling constants 17.6 Hz 9.7 Hz 6.4 Hz 2.0 Hz 6 5 The ir spectrum of 6Ji showed the necessary acetylenic absorptions at 3320 and 2120 cm' with the vinyl contributions displayed at 3080, 1645, 990 and 910 cm"\ The mass spectrum showed the parent peak to be m/e 106 with the base peak located at m/e 91, C^H-^ . Elemental analysis proved satisfactory for the CgH-jQ compound thereby establishing the identity of the hitherto unknown 65^. The acyclic octatetraene 6j5, predominating at 400° in the pyrolysate, was established as a secondary product derived from a 1,5 hydrogen shift in cyclopropane 6^, the sole product derived from collapse of the tricyclic octanylidenes to product. The origin of M was ascertained by

PAGE 64

55 independent flow (£) pyrolysis of gl pc-puri f i ed 6± at 410°. The octatetraene was obtained in 72% yield as the only readily-identifiable product with no tra^e of 6^ in the pyrolysate . The 100 MHz nmr of 6^6 showed a pseudo heptuplet of two-proton magnitude at 6 2.84 (H-). The olefinic region was more complicated giving rise to a two-proton pseudo pentuplet at 4.74 (H,), a three-proton multiplet region at 4.84-5.32 (H„, H.,, and H^) , and another three-proton multic I o plet region at 5.50-6.60 (H., H^, and H^). The proton assignments appeared justified on the basis of comparison with 66 a, 67 the nmr spectrum of the reasonable model compound 1,2,543 hexatriene (67_). The ir of 66^ possessed an absorption at 1955 cm" , confirmative of Lhe allene moiety. Other important

PAGE 65

56 absorptions attributed to carbon-caibon double bond groupings were noted at 3090, 3005, 1645, 1605, 995, 910, 845 and 740 cm" . The uv spectrum provided an absorption maximum at 225 nm, e 27,100. Since no compound possessing a ctH-butadiene structural feature has been demonstrated to 44 have an extinction coefficient greater than 10,000, it appears that 6j6, if a cis-trans mixture, contains a sizable trans component. Mass spectral analysis placed the parent peak at m/e 106 while elemental analysis proved satisfactory for the CoH,^ isomer. A summary of the basic reactivity of the syn and anti tricyclic heptanyl idenes and octanyl idenes shows that four C-,Hg monomeric and dimeric species and two C„H,^ monomeric species were isolated. As yet unanswered are (a) the stereochemistry of the ring fusion in 52^ and (b) the geometry of the butadiene moiety in 66^, Probably the most A 52 65 54-t 66 55

PAGE 66

57 interesting products in terms of continuing interest are the isomeric cycl opropanes 54-c and 54-t . Kinetic studies of both compounds will extend the body of knowledge surrounding the Cope rearrangement. Although not mentioned earlier, 54-t , while having proved stable at 169°C in solution, did rearrange quantitatively to give 52^ at 208° in solution as evidenced by uv and mass spectral fingerprints. Moreover, it would appear that 54-c , even without further kinetic examination, will lie between c7's -1 ,2-di vi nyl -cycl opropane ( 68) and cis -1 , ^-diethynyl -cycl opropane (6_9) in proclivity towards a Cope-type rearrangement: ' > > 68 Concerning the observation of cycloheptatriene and toluene in the pyrolysate obtained from the tricyclic heptanylidenes, it appears reasonable to say that the cycloheptatriene derives from a protonated 5-diazo tricyclic heptane (70) wh;ch, upon loss of nitrogen followed by cationic rearrangement, would afford cycloheptatriene. This hypothesis would be in keeping with the discussion of diazonium or

PAGE 67

58 carbonium ion intermediates (or both) obtained from ptosyl hydrazone salts when decomposition fails to exclude 2 a protic environment. The formation of toluene, which could derive from cycl oheptatri ene at hijh temperatures as 45 outlined by Woods, is also due in part to the breakdown of the p-toluenesulfinate anion since toluene was also observed in the pyrolysate afforded by the tricyclic octanylidenes. The end result is that cycl oheptatriene and toluene are not carbene-deri ved and warrant no further discussion. © '2 H 70 •No

PAGE 68

CHAPTER IV DISCUSSION AND CONCLUSIONS The question of paramount importance with regard to the isolation and characterization of the various products derived from the syn and anti tricyclic heptanyl i denes is an intriguing one: Do the observed products stem from the novel collapse of the carbene to 1 ,2 , 5 , -cycl oheptatriene (20) followed by rearrangement and/or dimeri zati on , or does ^is 1 -ethynyl -2-vi nyl -cycloprop.ine ( 54-c ) merit designation as the sole primary carbene product undergoing subsequent rearrangement to afford the other observed products? The answer to such a mechanistic question must be based upon (a) the observations thus far obtained (Chapter III) and (b) analogy appearing in the chemical literature 59

PAGE 69

60 Analogy or precedent was afforded by the remarkable insight of Sasaki and coworkers who proffered a novel explanation for the considerable difference of the carbene product distributions between the aldehyde and ketone p-tosy 1 hydrazones 46 71 and 72 It was concluded that the chrysanthemyl carbenes CH=NNH Tos 71 {cis and trans) C=NiNH Tos y+ H C=CH \ 2 2 68-73% CH, 72 ids and trans) 70-92% derived from ais and trans-72_ underwent largely fragmentation as opposed to ring expansion duo t.o a favorable electronic effect imparted by the isobutenyl moiety. The electronic effect would result in the lowering of the transition-state energy for the fragmentation process by virtue of formation of a conjugated dione, assuming the carbene reaction proceeded via either a concerted process or via a stepwise process involving either an ion-pair or radical pair:

PAGE 70

61 \ concerted radical pair ion pair In the case of the chrysanthemy 1 carbenes derived from aisand trans-72_, the ring expansion process predominated with exclusive migration of the i sobutefiy 1 -substi tuted bond (C3-C1 bond), again suggesting that the electronic effect of an isobutenyl substituent plays an important role at the transition state. However, another piece of rationale was required in order to explain the drastic difference in carbene product distributions despite obvious electronic control by the isobutenyl substituent. It was Sasaki's contention that the diversity of eye 1 opropyl carbene reactions, such as fragmentation and ring expansion, had been explained principally by consideration of strain and electronic factors without due cons 1 der .ti on of conformational effects. He advanced the notion that L he conformational effect played a ^ery significant role in determining the cycl opropyl carbene rearrangement reactivity. Maximum interaction of the carbene with the rearranging bond (the ring-expansion process) was possible wiien the substituent • assumed an s-trans-l i ke conformation against the cyclop >atie ring while an

PAGE 71

62 s-ais-Mke conformation afforded poor interaction, presumably facilitating fragmentation as the process of choice. S-trans S -c^s ''\ / R2 /^c \ / / — ^ R2 R3 The observed ring-expansion of the chrysanthemyl carbenes of 72^ was thus rationalized on the basis of the s-trans conformational effect while the chrysanthemyl carbenes of 7J_, minus the methyl substituent, were free to assume either conformation, the s-ais being probably no more or no less favored than the s-tpans with the electronic effect exerted by the isobutenyl moiety being the decisive factor.

PAGE 72

63 The development of the conformational effect as a tool in determining the cycl opropyl carbene rearrangement aptitude was further extended by Sasaki to geometrically constrained species, seme of which are locked into either an s-trans or an s-cis conformation. Whereas 7^, an s-trans species, underwent ring expansion exclusively, 7£, _75^, and 76 underwent the fragmentation reaction die to the s-cis structure presumably. (CH.) 73 n = 2,3 (CHp) 75 76 'V; In short, precedent as provided by Sasaki would regard eis-1 -ethynyl -2-vi nyl cyclopropane ( 54-c ) as the primary product most likely to be obtained upon collapse of either tricyclic heptanyl idene species to product. Cursory analysis of the basic results outlined in Chapter III would

PAGE 73

64 tend to argue in behalf of 54-c as the sole primary product since 54-c , once formed, p> ^ved extremely labile {^\/2 ^ 2-3 hours maximum) at 25° rearranging smoothly to dimer 5_2. Further, at present, there is no evidence to argue for reversibility in the formation of monomer 2j0 with the predominant formation of dimer 52^ under all pyrolysis conditions arguing for an essentially irreversible reaction leading from 54-c to _5_2_. The simple kinetic picture suggested by the observed reactivity of 54-c is supplied by the following reaction sequence treated by the steady state approximation:^^ h ^3 2C ^ 2M *D ^2 rate = d[D]/dt = k^ [M]^ d[M]/dt = k^ [C]^ k^ [M]^ k3 [M]^ C = cyclopropane 54-c =0 _ M = monomer 20 [M] = k]/^ [C]/(k2 + k3)^/^ D = dimer 52 d[D]/dt = k^k3[C]2/{k2 + k3) Assuming kp << k-, the rate expression would reduce to d[D]/dt = k,[C]^, the rate of formation of the intermediate,

PAGE 74

65 The intermediate, once formed, goes on to product rapidly. In this situation no equilibrium is established between re actant and intermediate, the intermediate (M = 2^) being dubbed a van't Hoff intermediate: Mechanism A. Reaction Coordinate 5^-c 52 Despite the foregoing discussion of precedent and the ensuing qualitative kinetic analysis, there remain some important questions tied into the exact identity of the

PAGE 75

66 primary product obtained from the tricyclic heptanyl idenes . Assuming 54-c to be the primary product, how does one account for the formation of trans 1 -ethynyl -2-vi nyl cyclopropane ( 54-t ) and 4-eth vnyl -cycl opentene (5^), products, which if they arise from 54-c , mubt do so by a nonconcerted process presumably involving biradical intermediates; i.e., 54-c would be forced to undergo epimeri zati on via cleavage of the C1-C2 bond to afford 54-c at lower temperatures (160°-400°C), while a 1,3 alkyl shift involving migration of the C1-C2 bond would afford 5_5 at higher temperatures (> 500°C). In reality such reactivity for 54-c does not l60°-400 ^^ ^^ > 500° seem plausible since it would mean that a Cope-type rearrangement, a well-established concerted process as outlined under orbital symmetry considerationb , would actually be in competition with a stepwise process. Further, examination of the activation energy parameters for cis -1 ,2-di vi nyl cyclopropane (68^), E = 19.38 + 1.80 kcal/mole, and ois1 ,2-diethynyl cyclopropane (69^), E^ = 22.7 kcal/mole.

PAGE 76

67 demonstrates the facile nature of the six-electron pericyclic reactions for such substituted cyclopropane systems. '° However, in the case of 69^ surface-catalyzed reactions in the gas-phase kinetics cast doubt on the exact nature of the rearrangement of 6J^. In contrast to the foregoing purportedly concerted pericyclic reactions, the cis-trans i someri zati ons of simple cyclopropanes typically afforded E^'s in the range 59.4-65.5 kcal/mole while 1,3 alkyl shifts of simple vinylcycl opropanes gave rise to E 's in the range 44.5-54.6 kcal/ a mol e 48 E^ = 60. 5 kcal/ mo le a / E, = 49.6 kcal/mole a The point to be made is at the heart of the di':.cussion of plausible mechanisms: if 54-c is the only true primary product, then 54-t and ^ must derive from a species other than 54^. At the same time, the low yields of 54-t (1,011.8%) and 55 (3.8-25.9%) suggest that the importance of these two products, however deserving of mechanistic scrutiny.

PAGE 77

68 should not be overly weighted so as to create havoc with the mechanistic pathway proving, in the final analysis, true for the tricyclic heptanyl idene systems. The suggestion to be made at this point is to also consider an alternative mechanism which could account for the observed products. In this alternative mechanism, 1,2, 5-cycl oheptatriene (2^) would arise via a novel six-electron reaction involving the carbene site and the C1-C6 and C2-C4 cyclopropane bonds, a postulate only briefly mentioned earlier in Chapter I. The application of the Mobi us-Huckel concept as applied to organic molecules and reactions by 49 Zimmerman to the cyclic arrays involved in bond-breaking and bond-forming processes in the transition states of the tricyclic heptanyl i denes shows that both systems possess Hlickel orbital arrays with the syn isomer ( 1 9-s ) having zero sign inversions while the anti isomer ( 1 9 a ) possesses four inversions. This is schematically ouHined below. The result of this simple analysis is Lhe tendency to accept the fact that either carbene could afford the monomeric species 2^ outright without invoking an intermediate such as 54-c . It should be noted that the foregoing Hiickel 2 arrays employ the p configuration of the carbene, an assumption which better accommodates the developing orbital overlaps em ountered in the transition state geometries of the respective carbenes as evidenced by inspection of

PAGE 78

69 Hlickel-Mobius syn Bond breaking Bond forming Bonds unchanged antr dark lobes: + of basis set light lobes: of basis set molecular models. Another examination of the possible "allowedness" of this carbene arrangement would be afforded by approaching the hypothetical arrangement from the viewpoint of a retro-cycl oaddi tion involving a tt^s + fr^s process for 1 9-s and a ir.a + Tr^a process for 19 -a wherein the respective it groupings have been tagged with the HOMO-LUMO designations derived from the Fukui Frontier Orbital approach to pericyclic reactions. The connecting lines between lobes of the same phase serve to demonstrate the demanded supraf acial -antaraf aci a 1 interactions which afforded the allene from the respective carbenes. Again it should be noted that the p configuration of the carbene

PAGE 79

70 2 + 4 retro-cycloaddition syn Lumo anti has been employed in describing the electronic interactions leading to the allene as product. The exact configuration of the carbene carbon in the tricyclic heptanyl idenes as well as the electronic makeup of the allene 20^ will be discussed further (vide infra), but first a hypothetical picture must be drawn based upon the primary formation and subsequent reactivity of 20: Mechanism B . Cope ^2 77 ID 55 a.

PAGE 80

71 Since it has been experimentally established that 54-c rearranges smoothly to 52_ presumably via 2^, then 20 , if first formed as speculated, would be in equilibrium with isolable 54-c , the rate-determining step being that leading to formation of dimer 5_2. In this sense 20^ would be an 1 3 Arrhenius intermediate and the energy profile would qualitatively appear as follows. Further, an understanding of the origin of products 54-t and 5^ would be more easily M = 2^ C = 54-c D = 52 Reaction Coordinate grasped since the initially formed species 2^ could be partitioned between singlet and triplet states, the triplet state giving rise to the open-chain biradical species 7^. which closes to afford either b4-t or 5^ depending upon the pyrolysis temperature employed. Since both singlet and triplet state Ciieiiiistry is observed for carbeiies in general, 1,2

PAGE 81

72 it is reasonable to assume that a triplet tricyclic heptanylidene species would give rise to a triplet all'ne species which could then fragment to give biradical TJ . A biradical such as Tl is a potential intermediate as evidenced by the assumed formation of such intermediates in the pyrolyses of (a) the salt of bicyclo [6.1.0] nona-2,4 6-triene carboxaldehyde tosyl hydrazone (78) and (b) . -cycl oheptatrienyl diazo me thane (79). 52 Na © NN-Tos — »/^^ ^ 79 I >— CH = N, '\j ^

PAGE 82

73 Contrast of the preceding discussion of Mechanism B against Mechanism A points to the fact that triplet 20 . obtained in Mechanism B by collapse of a small triplet component of the tricyclic heptanyl idene to triplet 2j0, would not be allowed under Mechanism A since, under the concerted process assumed taking place in the conversion of 54-c -» 20 -> 52 , singlet cyclopropane ( 54-c ) would give rise to singlet 2_0 which would dimerize as fast as it is formed. Two alternative mechanisms have thus far been proposed. A clear choice between the mechanistic alternatives must be left to the individual reader at this point. A third mechanism, which would invoke both 54-c and 2_0 as primary products via competitive formation from the carbene, would only serve to beg the question of mechanism, and hence is discarded. The structure and electronic character of 2^, the key intermediate of tricyclic heptanyl idene chemistry, deserves further consideration. The smallest cyclic aUenes isolated to date are 1 ,2-cycl ononadiene (80) and 1,2,63 A cyclononatriene (81). The smallest cyclic allene yet observed is 1 ,2-cyclohexad iene (2^) with 1 ,2-cycl oheptddiene (21 } not far behind in terms of framework distortion. As mentioned earlier in Chapter I, the observation of 2J_ and 22 is afforded only by isolation of their dimers and tetramers and the adducts resulting from trapping experiments. ' '

PAGE 83

74 80 81 In the smaller ring systems such as 2^ and 2^ the various authors have presented the vie\ o^nt that these systems must be something less than a fully-bonded allenic structure; i.e., research groups such as Ball and Lander ^ and Moore and Moser^^"^ have proposed that the Cg and C^ cyclic allenes possess a planar structure in which carbon atoms 1,2, and 3 are sp^ hybridized with unbonded i^lectrons for the singlet species (S^) residing in the hybrid orbital at C-2, while in the triplet species (T), one electron has beon promoted from the nonbonding hybrid at C-2 to the nonboiiding allylic orbi tal . 54 More recently Dillon and Underwood performed INDOMO calculations on a largf< number of distorted geometries of allene as a model for medium and small cyclic ai enes. Both the lowest singlet and triplet states were calculated; the effect of geometrical distortion on total energy, charge distribution, and spin distribution were also investigated. The calculations indicated that 1 ,2-cycl oheptadiene (and larger cyclic allenes) would have a singlet ground state best considered as an allyl cation with an anion located at

PAGE 84

75 basis set: dark orbitals: in plane 1 ight orbitals: out-of-plane S T C-2. On the other hand, 1 ,2-cycl ohexadi ene was shown by the calculations to most likely possess a triplet ground state best approximated by an allyl radical with a second unpaired electron occupying the in-plane orbital at C-2. Returning to the question of the initial carbene configuration of the tricyclic heptanyl i dene , it can be 2 seen that the singlet p configuration assumed earlier (note Hiickel -Mobi us and 2 + 4 r'etro-cycl oaddi ti un schemes) would give rise to a species formally containing an allyl anion with positive charge residing in the in-plane orbital at C-2, This arrangement of the singlet species disagrees with pre54 2 diction. On the other hand the lower-energy o configuration of the carbene, because of its disposition away from the internal cyclopropane bonds (C1-C6 and C2-C4) would not high energy singlet

PAGE 85

76 allow for the nece^^ary overlaps in the transition state leading directly to monomer 2^. In fact such an arrangement ^ low energy singlet would most likely afford 54-c , the primary product of Mechanism A, since no other reaction appear'possible. Thus determination of tiio singlet carbene configuration (a or 2 p ) for the tricyclic heptanyl idene might aid i : the choice of mechanistic alternatives. On the other hand, it must be 2 remembered that the demonstration of p character in carbenes such as the G:,n and anti tricyclic heptanyl i denes may not guarantee subsequent unique reactivity as would be ob2 served in the case of Mechanism B where the p configuration, assumed bi shomoaroniati c , 3upp;>st dly affords the novel six-electron pericyclic reaction leading to 20^. This caution arises from Bergman's assignment of bi sho loaromat i ci ty to J^, discussed in Chapter I, which undergoes the established fragmentation process as opposed to the novel pericyclic process. ^ dimer 8

PAGE 86

77 The point to be made in this discission about the electronic structure of 2_0 is that 2_U, if the primary carbene product of tricyclic heptanyl i denes , must arise by what appears to formally be a bi shomoaromati c carbene in a singlet process and would possess at least initially singlet character reverse that of prediction. As a matter of final interest, it would be of value to attempt to place the key C^Ho species on an energy surface although it would be only a crude approximation in the case of both 2C^ and the tricyclic heptanyl idenes themselves. 55 Employing Benson's additivity rules for the estimation of AH° kcal/ mole 10' 65 135 "strain free' -c::?

PAGE 87

78 thermochemi cal properties, 54-c , 541 . and 5_5^ are easily calculated allowing one less kcal/mole for the heat of formation of 54-t due to the missing ais interaction as would be observed in 54-c . The straightforward calculations afford values of 90, 89, and 66 kcal/mole for 54c , 54-t , and 5^, respectively. Employing Wentrup's extra56 polation of Benson rules to carbenes, a rough calculation of the energy of the tricyclic heptany 1 i dene species itself employing the heat of formation of triplet methylene (92 + 1 kcal/mole) for the carbene "group" affords a value of ca. 135 kcal/mole. Ring corrections used in obtaining this value are derived from bicyclo [3.1.0] hexane (32.7 kcal/ mole) and cyclopropane (27.6 kcal/mole). The value does not appear altogether unreasonable since 7-cycl oheptatrienyl methylene (82) has been calculated to possess a heat of formation of ca. 145 kcal/mole, a value whicf. serves to indicate that the heat of formation for certain suitablyconstructed Carliene species cin be rather high. On the 82 83 other hand carbene species such as 83^ have rather moderate heats of formation, AH° = ca. 68 kcal/mole. ^^

PAGE 88

79 The CyH„ vpecies most difficult to assess on tne energy surface is the monomer 20. Perhaps the best way to view this species energetically is to assume the view of 57 Dolbier who approximated a value for diradical 2j0 by first assuming a ir-bond energy in strain-free 20^ of 60 kcal/mole and subsequently subtracting out (a) 8 kcal/mole for the allene destabi 1 i zati on energy and (b) 15 kcal/mole for the ally! radical stabilization energy. The resulting value (37 kcal/mole) was added to the heat of fornidtion of "strainfree" 20^, 65 kcal/mole, to afford a final figure of 102 kcal/mole. This calculation, while only a rough approximation, probably represents a minimum value since Underwood's 54 INDO-MO calculations of 1 , 2-cycl oheptadiene (2J[) underscore the fact the 2J_ may indeed be a "di s torted" al 1 ene as opposed to a planar species, thus by analogy raising the energy of 20^ above the 102 kcal/mole figure approximated. While the energy diagram shows that the carbene will certainly convert to product(s), it is also obvious that activated 20^ should convert to some or all of the species below it on the profile. In passing it should be noted that the dimer 5_2 afforded a calculated heat of formation of ca. 88 kcal/mole, a value which is probably high due to lack of a suitable model for ring corrections. A discussion of the chemistiy of the tricyilic octanyl idenes is essentially a matter of tiie fragmentation

PAGE 89

process occurring for cycl opropyl carbenes . The idea that these systems could possibly give rise to the novel cyclic allene monomer bicyclo [5.1.0] octa-3 ,4-diene (8^) was developed early in the work with the tricyclic heptanyl idenes d i m e r 84 Whereas the p singlet of both tricyclic heptanyl i denes would possess to a certain degree paral 1 el geometry with regard to the adjacent cyclopropane rings, the tricyclic octanyl idenes in the p singlet state ould possess the bisected geometry which plays such a vital role in the on carbonium ion chemi stry of these systems. It was thought that this favorable added factor might help overcome the bi sected

PAGE 90

81 necessary energetics required for the trishomo interaction leading to monomer M. Molecular models showed that the syn species was especially well set for this type of interaction. It appears from the pyrolysis results, though, that any trishomo interaction in these systems will have to be established by trapping reactions with olefins and by Hiiiimett studies in order to disclose the el ctrophi 1 i ci ty or nucl eophi 1 i ci ty of these systems. The observance of the 1,5-hydrngen shift in the product cis1 -al lyl -2-ethynyl cyclopropane (6^), the only primary carbene product from the syn and ah ti tricyclic octany 1 idenes , is not without precedent since Dalacker and Hopf observed a facile 1,5-hydrogen shift in a related model compound, cis1 -ethynyl -2-methy 1 cyclopropane (85^), which smoothly converted to hexd 1 ,2 , 5tri ene 400' 1,5 65 66

PAGE 91

82 340°-530' 67 'V. n c o (67;) at the above specified temperatures. Analysis of conformational effects favoring a ready transfer oP hydrogen in 65 shows that the situation most favored would have an orientation where the vinyl group of the allyl moiety is oriented away from the neighboring triple bonded substi uent as pictured below. This 66 si uation would lead to a predominant formation of a tetraene (66) having tpans geometry for the butadiene moiety

PAGE 92

83 This is supported by the observed uv extinction coefficient of 27,100 for 6_6 as previously noted in Chapter III. In retrospect, the question of operational homoaromaticity in the tricyclic heptanyl i denes 1 9-s and 1 9-a and in the tricyclic octanyl idenes 25-s and 25-a has been raised. To fully answer the question, further work will be required in order to demonstrate the electrophilicity or nucl eophi 1 ici ty of said carbenes. It can be stated, however, that such homoaromati c reactivity appears a definite possibility for 1 9-s and 19-a due to the nature of the observed products. The case for 25-s and 25-a is not as promising and brings to mind a mechanistic consideration which should be afforded the fragmentation process of cycl opropylcarbenes since this mechanisticpathway may prove, in the final analysis, operative for both the tricyclic heptanyl i denes and octanyl i denes . The consideration afforded to the fragmentation process is one whereby the process may be visualized as a concerted process employing the cheletropic designation; i.e., a reaction in which two o-bonds wdich terminate at a single atom are made or broken in a concerted fashion The cheletropic disengagement of acetylene from ethylene with cyclopropyl carbene as reactant has been treated by Zimmerman previously giving rise to what is now known as 59 the Zimmerman MO following method. Recently Jones and Br inker presented an elegant simplified approach to the 47

PAGE 93

84 MO following method in general which allows for better visualization of the overall process leading from reactant to transition state to product. The following are the "rules of thumb," developed by Zimmerman and expanded upon by Jones and Brinker, which are put to use in constructing the schematic correlation diagram for the cycl opropyl carbene fragmentation process: (1) For the MO following, treat the carbene as the sum and difference of two "p" orbitals. "s" character is added after compatibility of reactant, transition state, and product orbitals is determined. Thus, during the "following," the orbitals of the lowest singlet state of methylene would be represented by LS-1 and LS-2 . Subsequent addition of "s" character to the orbital used in the reaction ((p-j + Pn) or (pi pn)) leads to the familiar filled sp^ orbital of the carbene and depending on the orbital used in the reaction, permits prediction of the orientation of the carbene during the reaction. LS-1 C (Pi + pJ c 6 and (i>cO = LS-2 (p, P.) f Add "s" Pi + P ^1 ^n Add "s" to (^ (Pr%)

PAGE 94

85 (2) Number the transition state linear arr.y beginning with one car bene orbital and ending with the other. (3) Assign the familiar linear polyene orbital signs to the transition state orbi tal s . (4) Follow each occupied reactant MO to product, using the carbene MO that is compatible with tue highest occupied transition state MO. (pp. 7-9) Thu<;, in conclusion of this chapter, the application of the Joiies-Bri nker extrapolation of Zimmerman's rules to the cycl opropyl carbene cheletropic reaction affords the following correlation diagram (Scheme V). The most impor52 tant observation to be obtained from the diagram is that, when "s" ciiaracter is finally added to the proper carbene orbital used in the reaction ( L S 1 vs. LS-2 ) under the auspices of rule 1, it will be added to p, + Pg ( [ , S 1 ) , the vertical p orbital, which correlates in symmetric fashion with the bonding product orbital tt-^' The qualitative result, an important one in light of preceding dis2 2 cussion concerning the reactivity of p vs. a singlet configurations of cycl jpropyl carbeties 1 9-s , 1 9-a , 25-s , and 25-a , is that the electron pair of the carbene must become oriented in an sp hybrid in the vertical plane (o). Once that posture is assumed only one mechanism is apt to derive, that of fragmentation. Closing the discussion on an optimistic note, suppose a structure such as 1 9-d through the favorable energetics imparted by homoaromat i ci ty , were able

PAGE 95

86 Scheme V Reactants Symmetry element: vertical plane (a) Transition State Products ^12^^6

PAGE 96

87 (P] + P5) + s only 2 ? -»sp ( verti cal ) = to obtain tha p configuration. Could one reasonably assume a different mode of reaction for such a carbene? The conclusion could \jery well be yes. (Pl Pg) ^ P'

PAGE 97

CHAPTER V EXPERIMENTAL Melting points were taken on a Thomas-Hoover melting point apparatus and were uncorrected. Infrared spectra of synthetic intermediates were recorded on either a PerkinElmer Model 137 or a Model 437 spectrophotometer while the spectra of pyrolysis products were recorded on a Beckhian IR 10 spectrophotometer. Nuclear magnetic resonance (nmr) spectra were obtained from a Varian Model A-60-A spectrometer and, less frequently, from a Varian Model XL-100 spectrometer. Mass spectral data wi-re obtained from both an Hitachi Perkin-Elmer RMU-6E mass spectrometer and an AEIMS 30 high-resolution mass spectrometer. Ultraviolet spectra were recorded on a Gary 15 double-beam spectrophotometer. Elemental analyses were carried out by Atlantic Microlab, Inc., Atlanta, Georgia. Glpc work, analytical and preparative, was performed on a Varian Aerograph ModelA-90-P3 gas chromatograph employing the cut-and weiyh method of analysis in analytical work. Four columns were used in glpc work and are referenced as follows: (1) column A 3% FFAP on Chromasorb P-Regular, 5 ft X 0.25 in aluminum. 88

PAGE 98

89 (2) column B 10% Carbowax 20 M + 3.5% KOH on Chromasorb P-Regular, 10 ft x 0.25 in a1 umi num. (3) column C 6% SE-30 on Chromasorb P-Regular, 5 ft X 0.2 5 in a 1 umi num. (4) column D lU/o DC-200 on Chromasorb P-Regular, 15 ft X 0.25 in copper. All compounds which were not referenced were commercially available. Preparation of di a llyl ketone (29,) . Tetramethyl -1 , 3-cycl obutanedi one (22) was pre1 g pared according to the procedure of Miller and Johnson: mp 113°-114° (lit^^ mp 115°-llb°). Reaction of allyl Grignard (1.25 moles) with 2^ (0.50 mole) using the procedure of Dreyfuss afforded 5-a 1 ly 1 -5-hydroxy--2 ,4 ,4trimethyl-y-octen-S-one (2_8) in 55% yield (lit^^ 61%). Base-catalyzed cleavage of 2_8 (22.5 g, 0.105 mole) employing barium hydroxide followed by distillation of the pyrolysate (bp 45°-57°/20 mm) on a 23 mm, 36 in Nester-Faust semi-works spinning band column afforded four fractions boiling (20 mm) at 32°-38°, 40°-4aV 49°-55°, and 55°-56°. Redistillation of the third fraction and combination with the fourth fraction gave 7.5 g (0.068 mole) of diallyl ketone (bp 55°-56°/20 mm, lit.^^ bp 51°53°/20 mm) contaminated with 5-10% allyl propenyl ketone.

PAGE 99

90 Net yield of 2^ was typically 62-64% (6.8-7.1 g, 0.0620.065 mole). Ir (film): 3025, 2960, 2920, 2870, 1730, 1640, 1420, 1385, 1360, 1325, 1285, 1215, 1135, 1105, 1070, 1050, 995, 920; nmr (CDCI3): 6 3.23 (d with splitting, J = 7 Hz, 4 H), 4.90-5.32 ( AB m, termi nal vinyl H, 4 H), 5.58-6.33 (m, 2 H); mass spectrum ( m/e ) : 110 (M ), 69 (M'^ C^Hg, major peak). Preparation of 2 ,2-di al 1y 1 -1 , 3-di oxol ane (M) . A solution of 5.95 g (0.0631 mole) of 29_ in 70 ml of benzene was mixed with 5.15 g (0.0830 mole) of ethylene glycol and 0.05 g of p-tol uenesul f oni c acid monuhydrate in a 200-ml round bottom flask. The flask was fitted with a Dean-Stcirk trap and a condenser (equipped with a drying tube). The mixture was refluxed until 1.1 ml of water had been collected (97% of the theoretical amount). The cooled reaction mixture was washed with 20 ml of 10% sodium hydroxide solution followed by five 10-ml washes with water. The benzene extract was dried over anhydrous K^CO^ and the benzene removed by rotary evaporation. The residual liquid was distilled at 20 mm affording 4.88 g (0.0316 mole) of 30^ (bp 75-76°, 50;). Preparative glpc on column A (column 82°, He flow 60 ml/min) afforded an analytical sample of 30. Ir (film): 3040, 2930, 2875, 1645, 1430, 1320, 1300, 1285, 1265, 1240, 1200, 1175, 1140, 1115,

PAGE 100

91 1080, 1040, 1000, 990, 920; nmr (CDCl^): 6 2.39 ( d with splitting, J = 7 Hz, 4 H), 3.90 (s, 4 H), 4.84-5.28 (AB m, terminal vinyl H, 4 H) 5.47-6.10 (m, 2 H); mass spectrum (iii/e_): 154 (M"^), 113 (M^ C3H5, major peak). Anal . Calcd for CgH^^O^: C, 70.10; H, 9.15. Found: C, 70.35; H, 9.11 . Preparation of cisand t2'ans-3 ,4-bi s (chl oromethyl ) cycl opentanone {IZY . A mixture of 6.75 g (0.0437 mole) of 30 and 12.1 g (0.0440 mole) of iodnbenzene dichloride ^ in 75 ml of chloroform was heatfd at reflux for two hours under a slow stream of nitrogen. The chloroform solvent was removed by rotary evaporation affording a slightly colored mixture containing iodobenzene and crude cisand t2'ans-7 ,8-bi s (chloromethyl )-l ,4-dioxaspi ro [4.4] nonane (3J_) . The ais-trans ratio of 3J_ was not established although the broad three-line inultiplet centered at 3.65 6 (-CH^Cl) indicated the presence of a ois-trans mixture. The iodobenzene was removed at 0,25 mm while heating the flask to 45°. Short-path distillation of 3J_ (bp 88"-95°/0.25 mm) afforded 6.80 g (0.0302 mole, 69%) of 3J_ possessing a brown tint (note: the use of hydroquinone stabilizer in distillations of 3J improved but did not eliminate decomposition). Crude 3_]_ (6.75 g, 0.0300 mole) was dissolved in 70 ml of 3:1 ethanol -water containing 200 mg of

PAGE 101

92 p-tol uenesul foni c acid. The solution was heated at 35°38° for 24 hours. The solution was poured into 500 ml of a saturated Na^CO, solution and extracted with three 200ml portions of ether. The combined ethereal extracts were washed with water until neutral followed by a final washing with 100 ml of saturated sodium chloride solution. The ethereal extract was dried over sod, urn sulfate and concentrated by rotary evaporation affording 5.11 g of an orange oil. The oi"" was fractionated through a short-path distilling head ( hydr oqu i none stabilizer) affording the desired di chl oroketone (32): 2.42 g (0.0134 mole, 45%). Ir (film): 2970, 2920, 1755. 1445, 1410, 1370, 1275, 1170, 1100, 770, 735; nmr (CDCI3): 6 2.17-2.58 (m,4H), 2.583.21 (m, 2 H), 3.57-3.80 (overlapping d, J^^^ = 'x^ "^ trans = 6 Hz, 4 H); mass spectrum (m/e) : 181 ( M"^ ) , 183 ( M"^ + 2, 66.3% of M"*"), 185 ( M"*" + 4, 11.1% of M"^ ) , 103 ( M"^ CoHyCl ; major peak) . 2 4 Preparatio n_ of f? ynand anLi-^tr^ c ycle [4.1.0.0 ' ] heptan 5ones (26_iS. and 16jia) : meth od A . A 2.42 y (0.0134 mole) mixture of crude cisand trans-Vl was added dropwise to a well-stirred 2.5 ml 50% sodium hydroxide solution in a 25 ml three-neck flask equipped with a sliort-path distilling head and a steam inlet (gas bubbler). After stirring for 30 min (reaction mixture had become black) a slow stream of steam was

PAGE 102

93 introduced accompanied by gradual heating of the dark reaction mixture to 150° (oil bath). The reaction mixture was heated for a minimum of 2 hr periodically introducing 3-4 ml of water to maintain solvent level. The oil-water distillate was extracted with three 100-ml portioiis of ether and the ethereal extract dried over MgSO,. Concentration by rotary evaporation afforded a light yellow (1.15 g) which was distilled affording 0.83 g of a colorless oil boiling 37°-42°/0.25 mm. The oil (.00769 mole, 57%) proved to be a surprisingly clean mixture of the syn (52%) and ant^ (48%) tricyclic ketons 26-s and 26-a by glpc on column B (column 150°, He flow 100 ml/min) with retention times of 15.7 min [anti) and 19.6 min [ayn) Anti isomer (26-a) : mp 41.0°-42.0° ( seal ed capil 1 ary , lit.^^ 44°); ir (CCl^): 2980, 1790(sh), 1720(s), 1440, 1340, 1295, 1190, 1145, llOO(w), 1075(w), 1050, 1030, 955(s), 935(s), 860; nmr (100 MHz, CDCl^): 6 0.85 (unsymmetrical q, J = 3.5 Hz, 2 H), 1.25 (m, 2 H), 1.56 (m, 2 H), 2.08 (m, 2 H); uv (ethanol): A„_ 287 nm (e 28); max mass spectrum ( m/e ) 108 (M ), 79 (M -CO-H, majur peak). Anal CaUd for C^HgO: C, 77.75; H, 7.46 Found: C, 77.61 ; H, 7.45. Syn isomer ( 26-s ) : ir (film): 2980, 1795(sh), 1700(s), 1455, 1315(sh), 1285, 1185, 1150(w), 1085(w), 1040, 1015, 950, 940, 925(w), 910, 825, 800; nmr (100

PAGE 103

94 MHz, CDCI3): 6 0.76 (m, 2 H), 1.50 and 1.7c (two overlapping multiplets, 4 H), 2.18 (m, 2 H); uv (ethanol): A 283 (c 70); mass spectrum (m/e): 108 (M"^), 79 max — — (M -CO-H , major peak) . Anal . Calcd for C^HgO: C, 77.75; H, 7.46. Found: C, 77.60; H, 7.53. Preparation of aisand trans-ethyl -2vi nyl -cycl opropane carboxylates ( 3_5)~. Cisand trans-3S_ were prepared from butadiene and freshly-prepared ethyl diazoacetate in 28-32% yield following the procedure of V gel, Erb, Lenz, and Bothner25 By, Analysis of the isomer mixture by glpc on column A (column 100°, He flow 25 ml/min) showed the ais trans ratio to be 40:50. Bp 63°-64°/13 mm (lit."^^ 61°-62V12 mm); ir (film): 3000, 2905, 2;.50, 1720, 1640, 1435, 1390, 1375, 1345, 1315, 1300, 1280, 1260, 1180, 1090, 1035, 990, 905, 880, 860, 850, 820, 795, 740; nmr (00013): 6 0.80-2.23 (m, 4 H), 1.28 (t, J = 7 Hz, 3 H), 4.15 (q, J = 7 Hz, 2 H), 4.83-6.18 (m, vinyl H, 3 H); mass spectrum ( m/e ) 140 (M"^), 67 (M"^ CO2CH2CH3, major peak). Anal . Calcd for CgH^202: C, 68.54; H, 8.63. Found: C, 68.27; H, 8.62 Preparatio n of cisand i!:r'ans-2vi ny 1 -cycl opropanecarbony 1 chlorides j^) '. Treatment of 100 g (0.713 mole) of cisand trans 35_ viith 78.0 g (1.40 mole) of potassium hydroxide

PAGE 104

95 in 400 ml of 50?:! methanol according to the procedure of 25 Vogel and coworkers afforded 72.5 g (0.647 mole) of c7;snd trans-2-vi nyl -1 -eye i opropanecarboxyl ic acids (36.): bp 80°-82°/0.6 mm, 91%; lit.^^ bp 52°-54°/0.05 mm, 90%. A mixture of oisand trans-^ (69.0 g, L.616 mole) was converted to the corresponding 2-vi ny 1 -cycl opropanecarbonyl chlorides 37^ (73.5 g, 0.561 mole, 90%) by treatment with 370 g (3.10 mole) of freshly-distilled thionyl chloride. The aisi -ans mixture of 2]_ was analyzed by converting several drops with methanol to the corresponding methyl esters, which were chromatog* aphed on column A (column 100°, He flow 30 ml/min). The cistrans ratio was found to be 38:62. Bp 47°-48V8-9 mm (lit.^^ 19"-50°/ 11 mm); ir (neat, KBr liquid cell): 30U5, 2930, 1770, 1640, 1430, 1350, 1295, 1230, 1190, 1150, 1110, 1080, 1060, 995(s), 91b(s), 880(s), 810, 750, 725(s), 680(s); nmr (CDCI3): 6 1.05-1.90 (m, 2 H), 1.95-2.80 (m, 2 H), 4.92-5.98 (m, vinyl H, 3 H) . Preparation of oisand tfans-'] -di azomethy 1 keto-2vinyl cyclopropanes ( 38) . A solution cif 25.8 g (0.460 mole) of potassium hydroxide in 43 ml water, 150 ml of diethyleno glycol monoethyl ether, and 35 ml of ether were placed in a 500 ml Claisen flask equipped with a dropping funnel, a condenser, and two 500-ml Erlenmeyer receivers employing the

PAGE 105

96 basi' set-up described for di azoinethane generation. The flask was heated at 65°-70° in a water bath while a 92.5 g (0.432 mole) solution of Diazald (N-methyl -Nni troso-pto 1 uenesul f onami de , Aldrich) in 450 ml of ether was added dropwise over a period of 90 min. The ethereal diazomethane {'\^ 12.9 g, 0.307 mole) was dried over KOH for 90 min at 0°. A solution of aisand trans-37_ (10.0 g, 0.0763 mole) in 20 ml of ether was added quickly dropwise to the dried ethereal diazomethane and the resulting solution was allowed to stir overnight at 25°. The yellow ether solution was concentrated by rotary evaporation giving an orange-yellow oil ('v^lO.Og, 0.0735 mole) which was employed directly in the next step. Ir (film): 3030, 2940, 2100(s), 1720, 1640(s), 1440, 1390(s), 1325(s), 1205, 1180, 1165(s), llOO(s), 1075(s), 1040, 995, 965, 910(s), 885, 840, 815, 785, 770, 720; nmr (CDCI3): 0.752.28 (two overlapping m, 4 H), 4.77-5.84 (m, vinyl H, 3 H) , 5.31 (s, diazomethyl H, 1 H) . Preparation of si^n and antf tri cycl [4.1.0.0^ ''^ ] heptan5-ones (T^iS. and j^ j^a.) : method B . The crude diazoketone 38 (% 10.0 g, 0.'")735 mole) was dissolved in 100 ml of cyclohexane and added dropwise over a period of 2 hrs to a refluxing slurry of 400 ml of cyclohexane and 25 g of anhydrous CuSO.. Upon completion of the addition and further stirring for 1 hr under reflux

PAGE 106

97 the slur'ry was filtered and concentrated via rotary evaporation affording an orange-red oil. The oil was fractionated (short-path column) giving a fraction (slightly yellow) boiling 35°-44°/0.5 mm and weighing 2.95 g. Nmr spectral inspection indicated the distillate to be composed of the desired 26-s and 26-a contaminated with by-products possessing the vi nyl -cycl opropane skeleton. Preparative glpc on column B afforded analytically pure samples of the isomeric tricyclic ketones. Column chromatography on silica gel (described next) afforded 1.01 g (.00935 mole) of separated 26-s and 26-a (32% from the ds-acid chloride). The synanti ratio was 47:53. Anti isomer ( 26-a ) : /^ nal . Calcd for CyHoO: C, 77.75; H, 7.46. Found: C, 77.56; H, 7.42. Syn isomer ( 26-s ) : Anal. Calcd for C-,HgO: C, 77.75; H, 7.46. Found: C, 77.85; H, 7.47. Purific ation and s eparation of syn' a nd ant-^-tri cycl o [4.1 .0.0^»^ 1 heptan-5-ones (Z£^lS. and 2Jis^) . A crude 7.50 g mixture (distillate from several runs) of 26-s and 26-a obtained from reaction method B (diazoketone route) was chromatographed on 200 g (56 cm column height) of silica gel (MCB, G. 62) by eluting (dropping rate: 15 drops/iiiin) with '^ 900-950 ml of carbon tetrachloride which both removed major impurities and effected separation of 26-s and .26-a. The faster-moving

PAGE 107

98 syn isomer was stripper from the columi by e'ution with 'V; 600 ml of 1:1 carbon tetrachloride-methylene chloride followed by "^ 400 methylene chloride which served as a transition solvent between the syn and anti isomers (the use of methylene chloride required monitoring by glpc on column B of the eluent). The appearance of the anti isomer was accompanied by elution with ether v.hich flushed the slower-moving isomer from the column. Final purification of the separated isomers was achieved by short-path distillation which removed traces of colored materials. The syn distillate proved absolut ly free of the anti isomer while the anti distillate contained 2.3% of the syn isomer (by qlpc). The syn-anti distribution was 1.20 g:1.36 g (47:53). ^he syn-anti mixtures obtained from reaction method A ( bi s-chl oromethyl -k :one route) were separated in the same manner; a final distillation was found unnecessary since the distilled starting mixture of isomers w.is cleaner than the mixture obtained from method B. The ami isomer obtained f om the combination column chri a tography-disti 1 1 ati on work-un w.s observed to crystallize upon standing, affording a moist white soM'd melting 39.5°-41.0' (glpc sample: 41 . 0°-42 . 0° ) .

PAGE 108

99 Eu(fod)3 shifts in the 'H nmr spectra of si/nand anti-tricycio [4.1.0.0^'^] heptan-5-ones : structure assignment . Treatment of 0.8 ml deuterochl orof orm solutions of 26-s (0.0470 g, 4.35 x 10"^ mole) and 26-a (0.0789 g, 7.31 X 10" mole) with Eu(fod)2 in varying molar ratios produced interesting 1 anthan ide-i nduced shifts in the 60 MHz 'H nmr spectra. Assuming the lanthanide atom to lie o at a 3.0 A distance from the oxygen atom (of each respective isomer) in the plane bisecting each system, the various lanthani de-proton distances and proton-Eu-C^ angles were determined manually from a Ureiding model. Rough 3 1 dc calculations of the agreement factor, R^, employing shift dcitu at maximum mole ratio, afforded R = 0.16 for 26-s and R = 0.23 for 2_62a_. Based upon these rough calculations of R and the observed lanthani de-induced shifts in the 'H nmr spectra, the proton assignments of 26-s and 26-a were established for both the 60 and 100 MHz spectra (see Table III). Preparation of bicyclo [3.1.0] hex-3-en-2-one (42) . Bicyclo [3.1.0] hexan-2-one (39) was prepared in 43% yield following the procedure of Nelson and Mortimer (lit. 64%) from 4tosyl oxycycl ohexanone . Bicyclic ketone 39^ was also prepared by the cycl opropanation of 2-cycl opentenone in 69% yield according to the procedure

PAGE 109

100 Table I. 26-s + Eu(focl) 3 Molar ratio: Eu(fod)g/26-s H H, H, H 1 "2 3 4 (Hz downfield from TMS at 60.0 MHz) 0.00 0.13 0.25 0.38 0.50 100 182 279 360 440 132 159 193 221 251 90 129 173 213 251 45 67 97 123 148 Table II. 26-a + Eulfod)^. Mol ar rati o : Eu(fod)„/26-a H H, H. H 1 '2 3 "4 (Hz downfield from TMS at 60.0 MHz) J

PAGE 110

101 So Q. 00 N O O +-> c: I 10 t s. o c: Ol E c en •I— I/) (/) <: c o o i. (U

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102 Russ'-^l and coworkers^^ (lU. 65%): bp 60°-62°/10 mm (lit.^^ 55°/10 mm); mass spectrum (m/e^) 96 (M"^), 68 (M"^ CO, major ,eak). The bicyclic ketone (4.0 g, .042 mole) was dissolvec in 50 ml of ethylene glycol and treated dropwise with bro, ine (6.8 g, .043 mole) at 25°-38°. The solution became cloudy upon completion of brofiilne addition and was allowed to stir for 10 min longer. The solution was poured into a mixture of 14 g of NapCO^ in 100 ml of pentane. The pentane layer was separated and dried over Na^SO,. Concentration by rotary evaporation arforded o.73 g of a colored oil which was dissolved in 100 ml of DMSO (distilled from CdH^). To the solution (under nitrogen) was added pinchwise sodium methnxide (3.78 g, 0.0701 mole) at 25°-35°. The almost black reaction mixture was stirred at 25° for 9 hrs and then gradually heated to 60° for 15 hrs. The black mixture was poured into 500 ml of HpO and extracted with five lUO-ml portions of pentane and the pentane extracts were dried over NapSO.. C^ncentratior, via rotary evaporation afforded an orange liquid which afforded the ethylene ketal (4J ) of 42 (bp a4°-90°/ .^0 r i; lit.^^ bp 89°-95°/28 mm): 1.65 g, 0.0119 mole, 29% from 39^. Generation of 42^ from 4J[ was accomplished by shaking 10.0 g (0.072b mole) of 4^ with 14 nil of 3% H2S0^ for 10 minutes in a separatory funnel. The reaction mixture was extracted with three 50-ml portions of ether

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103 and dried over K^CO-. Distillation of the.concentrated liquid re:.idue afforded 3.98 g (0.0423 mole) of 42^ (bp 64°-67°/10 mm): 58% yield from 4J^. Glpc on column A (column 95°, He flow 60 ml/min) arforded analytically pure 4^. Ir (film): 3010, 2940, 1695(s), 1620, 1555, 1425, 1340, 1300, 1285, 1180, 1155, 10'^'\ 1060, 1035, 990, 955, 915, 855, 825(s), 810(s), 765, 735; nmr (CDCI3): 6 1.171.68 (m, 2 H), 2.15 and 2.50 (two overlapping m, 2 H), 5.62 (d, J =6Hz, 1 H), 7.68 (d of d, J = 6 and 3 Hz, 1 H); uv (ethanol): A^_ 324 (e 20), 252 (e 2490), 213 (e 7120); max mass spectrum ( m/e ) : 94 (M ), 66 (M CO, major peak). Found Anal . Calcd for C^HgO: C, 76.57; H, 6.43. C, 76.45; H, 6.44. 2 4 Preparation of gnt^-z:tri cycl [4 .1.0.0 ' ] heptan-5-on e T2t-T r Oil-free sodium hydride (0.80 g, 0.033 mole) was added to 50 ml of anhydrous DMSO (distilled from CaH2) in a 100-ml 3-neck flask equipped with a solid addition funnel, a condenser, a liquid dropping funnel, and a N^ inlet. To the mixture was added 7.60 g (0.0345 mole) of trime f-.hyl sul f oxoni urn iodide pinchwise. The resulting solution was allowed to stir for 30 min at 25° whereupon 2.81 g (0.0^99 mole) of 42^ in 10 ml of anhydrous DMSO was added slowly dropwise. The solution became orange-brown in color and was stirred at 25° for 2 hrs followed by

PAGE 113

104 heating at SS^-SO" for 30 min. The solution was poured into 250 ml of HpO and extracted with three 150-ml portions of ether. The ethereal extracts were washed with 100 ml of saturated NaCl solution and dried over Na^SO,. Filtration and concentration via rotary evaporation of the ether solution afforded an orange oil (2.74 g) which was distilled through a short-path column at 0.25 mm (bp 36°-38°). A 2.14 g (0.0198 mole, 66%) fraction of 26-a (white solid) WdS obtained which partially clogged the condenser and receiver elbow: mp 40 . 5°-41 . 5°; 1 i t . mp 44°. Glpc analysis on column B showed the syn-anti ratio to be 2.2:97.8. Anti isorier ( 26-a ) : Anal . Calcd for C-,Hg0: C, 77.75; H, 7.46. Found: C, 77.59; H, 7.45. 3 5 Prep a ration of methyl -tri cycl o [5.1.0.0 ' ] octyl-2 carboxylates (ASJ : isomeric mixture . Methyl-l,2-d i hydrobenzoate (44^) was prepared in 30 90% yield by treatment of 1 ,4-d i hydrobenzoi c acid (43) (30.0 g per run, 0.242 mole) with al cohol -f ree , KOH-dried ethereal diazomethane {"^ 22 g, 0.52 mole) generated from N-methy 1 -N-ni troso-ptol uenesul f onami de (Diazald): bp 44°-4670.75 mm; lit."^*^ bn 33V0.5 mm. Treatment of 36.5 g (0.264 mole) of 44^ according to the 30 procedure of Lambert and coworkers employing methylene iodide and either the Lambert zinc-copper couple or the LeGoff couple^^ afforded ^ 17.1 g (0.103 mole) of 45

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105 30 (isomeric mixture, 40%; lit. 40%). Glpc analysis on column C (column 130°, He flow 50 ml/min) indicated the presence of two principal isomers {ais, eis and aid, trans45) . Spectral and elemental analysis of the isomeric mixture (bp 45°-46°/0.5 mm; lit.^° bp 45°/0.5 mm) afforded the following: ir (film): 2990, 2950, 2870, 2830, 1730(s), 1470, 1445, 1430, 1360, 1340, 1310, 127b(s), 1245(s), 1180(s), 1130, 1105, 1085, 1020(i,), 935, 895, 870, 845, 810, 755, 715; nmr (CDCl^): 6 -0.08-1.65 (complex m region, 8 H), 2.10 (narrow m, 2 H), 3.45 (broad t, 5.5 Hz, 1 H), 3.72 (s, 3 H); mass spectrum (m/e): 166 (rl"^), 79 (CgH^ , major peak) Anal . Calc Found: C, 72.27; H, 8.54. Anal . Calcd for ^'^Q^^^0^: C, 72.26; H, 8.49; 3 5 Preparation of ai s, ais and ais, tranet ri eye 1 o [5.1.0.0 ' ] oct-2-yl acetates (A7_) : isomeric mixture . 3 5 Tricycl i [5 . 1 . 0. ' ] octyl -2-carboxyl i c acid (46) was prepared by trijatment of 17.1 g (0.103 mole) of 45 with 360 g of 10% NaOH solution according to the pro30 cedure of Lambert (lit. yield 76%). The crude acid (12.1 g, 0.0793 mole, 77%) obtained was dissolved in a solution of 10 ml of anhydrous pyridine (distilled first from tosyl chloride, then from CaH^, and stored over 4A sieves) and 250 ml of benzene (dried by passing through Woelm basic alumina, activity I, under nitrogen).

PAGE 115

106 Tho acid solution was placed in a 500-ml 3-neck flask equipped with a condenser, a nitrogen inlet tube and a mechanical stirrer. The system was flushed for 20 min with nitrogen, and lead tetraacetate (53.5 g, 0.121 mole) was quickly introduced f>llowed by gradual heating of the mixture to reflux. The mixture was refluxed for 1 hr; a heavy white precipitate of lead diacetate was observed to have formed subsequent to the vigorous evolution of CO^ during the reaction. The reaction mixture was filtered and washed with one 75-ml portion of H^O, two 75-ml portions of IN NaOH solution, one 75-ml portion of H^O, one 75-ml portion of IN^ HCl , and two 75-ml portions of H^O. The benzene extract was dried over MgSO,, filtered, and twice distilled to give 7.31 q (0.0'!141 mole, 56%) of isomeric acetates 47 boiling 60'--63°/0.5 mm (lit.^^ bp 55V0.1 mm). Spectral and elemental analysis of the acetate mixture (glpc on column C, 135°; He f , ow 60 ml/ min) gave the fnlluwiny: ir (film): 29bU, ; 950, 2850, 2820, 1725(s), 1475, 1440, 1350, i::'40(s), 122 , 1135, 1080, 1030(s), 1005(s), 955(s), b80, 845, 780, 735; nmr (CDCl^): (^ -.06-1.50 (complex m region, 8 H), 1.55-2.32 (m, 2 H). 2.07 (s, 3 H), 5.20 and 5.82 (m and t, respectively, CHOAc of two isomers present, 1 H); mass spectrum (m/e): 144 (M"*", < ]%) , 93 (C^Hy"*", peak second in intensity), 91 (C^H-,"^, major peak).

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107 Anal . Calcd for C^qH^^O^: C, 76.26; H, 8.49 Found: C, 72.19; H, 8.51 . 3 5 Preparation of syna nd antt-tri cycl o [5.1 . . ' ] octan2-ones (49-s and 49jiTy^ A mixture (3.55 g, 0.0214 mole) of the isomeric acetates 47 was dissolved in 35 ml of ether (anhydrous) and added slowly dropwise to a slurry of 0.900 g (0.236 mole) of lithium aluminum hydride in 75 ml of ether employing a 250-ml 3-neck flask equipped with a condenser, an addition funnel, and a stirrer. The reaction mixture was held at reflux for 30 min subsequent to completion of acetate addition. The cooled mixture was caretully hydrolyzed with 3.5 ml of 5% NaOH solution. When the solids in the flask had turned white, the mixture was filtered. The white solids were boiled twice with tetrahydrof uran whereupon the tetrahydrof uran-ether extracts were combined, dried over MgSO., filtered, and concentrated by rotary evaporation. A crude mixture of isomeric tricyclo [5.1.0.0^'^] octan-2-ols (48) was obtained (2.55 g, 0.0206 mole, '^ 96%): ir (film): 3300(s); nmr (00013): 6 4.12 and 4.73 (pseudo d and t, respectively, CH-0 of two isomers present, 1 H). A crud. mixture of isomeric 48^ (2.70 g, 0.0217 mole) was oxidized by dissolution in 50 ml of acetone followed by titration with Jones reagent (2.7 \\_

PAGE 117

Iu8 solution) at 15°-20° until the persistence of a yellow color was noted. The excess reagent was quickly destroyed with isopropyl alcohol and liO ml of HO was added to dissolve the inorganic precipitate. The resulting aqueous solution was extracted with five 8O-111I portions of ether. The ethereal extracts were dried over MgSO., filtered, and concentrated via rotary evaporation. The crude product (2.39 g) was distilled through a short-path column affording 2.05 g (0.0168 mole, ^ 76%) of moderately pure 49-s and 49-a : bp 53°-54°/0.5 mm. Glpc on co:umn B {syn-anti ratio, 77:23) afforded analyticcilly pure samples of the tricyclic octanones (column 175°, He flow 120 ml/min) with retention times of 14,4 min [anti) and 22. B n. , n {syn) . Anti isomer ( 49-a ) : ir (film): 3010, 2960, ?875, 2810, 1680(s), 1435, 1380, 1310, l;-:40, 1190, 1100, 1050.. 1025, 970, 915, 835, 720; nmr ^CDLl^): 6 0.68 (narrow m, 2 H), 0.85-1.70 (m, 6 H), 2.13 (narro m, 2 H); uv (ethanol): X 283 (e 28); ma :s pectrum (m/e): 122 (m"^), 55 (M"^ III O A ' CgHy, major peak). Anal . Calcd for CgH^QO: C, 78.65; H, 8.25; C, 78.45; H, 8.22. Syn isomer ( 49-s ) : mp 43.5°-44.5°; ir (film): 3010, 2970, 2b75, 2810, 1660(s), 1450, 1440, 1350, 1320, 1255, 1240, 119i, 1120, 1030, 1015, 970, 960, 925, 885, 840, 725, nmr (CDCI3): 6 1.02 (m, 4 H), 1.73 (m, 4 H),

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109 2.27 (narrow m, 2 H); uv (ethanol): X^^^ 284 (e 40); mass spectrum (m/e^) 122 (m"^), 55 (m"^ C^H^, major peak) Anal . Calcd for C^H^qO: C, 78.65, H, 8.25; C, 78.68; H, 8.25. Purification and separation of synand ant?'tri cycl o [S.l.O.O^'^l octan-2-ones (49-s and 49-a) . Attempted separation of 49-s and 49-a by column chromatography (silica gel and alumina) according to the procedure employed for the isomeric tricyclic heptanones ( 26-s and 26-a ) proved inefficient. Separation of 49-s and 49-a was effected by subjecting the initially distilled mixture of ketones to four consecutive short-path distillations (0.5 mm) gradually raising the oil bath temperature from 25° to 68° over a time period ranging from 7.5-10 hrs. The anti isomer di M'lled first; fractions en^ riched in the syn isomer led to the crystallization of a white sol^d in the condenser-receiver pathway. The slightly tinted pot residue obtained at the end of a distillation proved to be pure 49-s . solidifying upon standing. An anti fraction (1.10 g, 0.00902 mole) collected in this manner proved 96.1% free of the syn isomer while a syn fraction (2.64 g, 0.0216 mole) proved 98.4% free of the anti isomer (by glpc on column A, 130°; He flow 120 ml/min) .

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no Preparation of tosy1 hydrazones . The lability of 26-s , 26-a . 49-s , and 49-a in the presence of acid precluded acid-catalyzed formation of the respective tosyl hydrazones . The respective tosylhydrazones were prepared by stirring equimolar quantities of ptol uenesu 1 f onyl hydrazide and the ketone in absolute ethanol (1 g/25 ml) for 21-24 hrs (25°). A notable exception was 26-s which wthin five min after mixing led to the precipitation of the desired tosyl hydrazone ( 3 3 s ) ; the resulting slurry was stirred for only 2 hrs before work-up. The crude tosyl hydrazones obtained from 26-a , 49-s , and 49-a upon removal of solvent were first chromatographed on silica gel (methylene chloride eluent) and thrn recrystal 1 ized from ethanol at 0°. Tosyl hydrazone 33-s required only recrys ta 1 1 i zati on from ethanol. 5!/ntri cycl o [4.1.0.0^'^j heptan-5-one tosyl hydrazone (33-s) : 83% yield; mp 176.0°-l/8° (dec); ir (KBr) 3350, 3150, :530, 1580(sh), 1450, 1390, 1370, 1330, 1310, 1295, 1180, 1160(s), 1085, 1040, 1015, 940, 900, 825, 810, 720, 705; nmr (CDCl^): 6 0.78 (m, cyclopropyl methylene H, 4 H), 1.96 (m, cyclopropyl methine H, 4 H); 2.40 (s, -CH^, 3 H), 7.47 (s, -NH, 1 H), 7.53 (ABq> aromatic H, 4 H); mass spectrum (m/e) 276 (M^), 91 (C^H^"*, major peak). Anal . Calcd for C^^H^gO^N^S: C, 60.85; H, 5.84; N, 10.14. Found: C, 60.82; H, 5.84; N, 10.19.

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m i4nti-tri cycl [4.1.0.0'"' ] heptan-5-une tosylhydrazone ( 33-a ): 31% yield; mp 132°-13 (dec); ir (KBr): 3350, 3150, 2850, 1540, 1590(sh), 1480, 1430, 1335, 1335. 1320, 1310, 1300, 1180, n60(s), 1085, 1025, ^010, 935, 895, 820, 805, 725, 715, 705; nmr (CDClJ: 6 0.52 (m, cycl opropyl -e;nJo H, 2 H), 1.03 (m, cycl opropyl -exo H, 2 H), 1.70 (m, cyclopropyl methine H, 4 H), 2.40 (s, -CH^, 3 H), 7.27 (s, -NH, 1 H), 7.58 (ABq, aromatic H, 4 H); mass spectrum {m/_e) 276 (M"*"), 91 (C^H^"*", major peak). Anal . Calcd for C,.H,g02N2S: C, 60 8!. . H, 5.84; N. 10.14. Found: C, 60.82; H, 5.86; N, 10.1,. 3 5 5yn-tricyclo [5.1.0.0 ' ] octan-2-one sylhydrazone ( 50-s ) : 42% yield; ip 14 ^-146° (dec); ir (KBr): 3350, 3180, 2950(w), 2880(w), 1605 (doublet), 1435, 1410, 1360, 1325(s), 1280, 1160(s), 1120, 1075, 1035, 990, 930, 875, 850, 830, 815, 760, 735, 705; nur (CDCI3): 0.08-2.03 (complex m region, cyclopropyl methylene and methine H, 8 H), 2.15 (pseudo t, -CH^-, 2 H), 2.40 (s, •CH3, 3 t!). 6.68 (broad s, -NH, 1 H), 7.60 (ABq, aromatic H, 4 H); mass spectrum (m/e) 290 (M ), 91 (C7H-, , major peak). Anal . Calcd for C^gH^g02N2S: C, 62.04; H, 6.25; N, 9.65. Found: C, 62.13; H, 6.28; N, 9.60. 3 5 Anti~tr]cyc]o [5.1.0.0 ' ] octan-2-one tosylhydrazone ( 50-a ) : 34% yield; mp 138°-141° (dec); ir (KBr): 3350, 3150, 2850(w), 1605 (doublet), 1430, 1390, 1355,

PAGE 121

112 1320, 1275, 1160(s), 1080, 1025, 980, 955, 905, 845, 830, 820, 725; nmr (CDCl^): -0.22 (m, 1 H), 0.60-1.98 (complex m region, 8 H), 2.17 (m, 1 H), 2.40 (s, -CH^, 3 H), 7.35 (s, -NH, 1 H), 7.60 (ABq, aromatic H, 4 H); mass spectrum ( m/e ) 290 (M ), 91 (C^H-^ , major peak). AnaJ_. Calcd for C^gH^g02N^S: C, 62.04; H, 6.25; H, 9.65. Found: C, 62.00; H, 6.27; N, 9.71. Preparation of sodium and potassium salts of tosy 1 h.ydrazones The sodium salts of 33-s , 33-a , 50-s , and 50-a were prepared under nitrogen (dry box) by dissolving the respective tosyl hydrazone in dry tetrahydrof uran (refluxed over and distilled from lithium aluminum hydride) in the ratio of 1 g/35 ml and adding 1 ? equiv of oil-free sodium hydride (Alfa Inorganics) pinchwise with rapid stirring. Stirring was continued for an additional 2 hrs. An equal volume of pentane (spectrograde) was added to the tetrahydrofuran slurry (most of tho desired salt had already precipitated from the tetrahydr ofuran solut'on). The white precipitate was filtered, dried under full vacuum, and stored in an amber bottle in the dry box. Yields for the four sodium salts were in tne range 97 . 8-'\^l 00% . Similar preparation of the potassium salts of tosy 1 hydrazones 33-s and 33-a was effected by treatment of the respective tetrahyd>^o-'~uran solution with 1.2 equiv of lotassium

PAGE 122

113 tert -butoxide (Alfa Inorganics). Work-up with pentane and drying afforded the potassium salts of 33-s and 33-a in quantitative yield. Pyrolysis of tricydo ketone tosyl hydrazone sodium salts . The two principal pyrolytic techniques employed were the (1) drop-static (D-S) technique and, to a lesser extent, the (2) flow (f) technique. The first technique involved controlled dropping of the sodium salt on a heated glass surface {160°-500°) under high vacuum (7 x 10 3 x 10" mm). High-boiling products (chiefly dimeric material) were immediately trapped by a cold finger disposed 3.5 cm above the heated surface while volatile products were collected in a 35 cm co'l t»ap (cooled by liquid nitrogen) in line with two smaller back-up traps (^ee figure 11) The pyrolysis vessel (Pyrex) used for this work was ?imply a sublimator modified with a storage neck for solids, a Rotaflo high-vacuum stopcock (Quickfit, Inc.), and a conducting tube. Adjustment of the stopcock opening allowed the sodium solt to drop from the storage i-eck, through the conducting tube, to the heated glass surface. Either dry ice-acetone or ict-H^G was employed as the cold fir er coolant. The second technique employed controlled dropping of the sodium salt dov.M a "not tube." Two tubes (Vycor) were used, the first having a 30 cm heat zoni the second

PAGE 123

114 a 40 cm heat zone. Both tubes were designed with 120° bends at tlie top of the heat zone which was constructed from 24 nauge nichronie wire and asbestos tape. The tube was connected first to a solid collection trap followed by the same trap system for volatile products described for the drop-static technique. A third 1 ess-f requently used technique was the basic static (S) technique in which the entire sodium silt aliquot was simply placed in the bottom of a sublimator and pyrolyzed. Heating of the sublimators used in the pyrolytic work was accomplished by the use of a Wood's metal bath. Monitoring of temperatures was accomplished by using chromel -al umel thermocouples in conjunction with a Minneapolis-Honeywell Model 2702 potentiometer. Nitrogen evolution during pyrolysis of a sodium salt was monitored by a Idlevac Mode 2A thermocouple vacuum gauge (Fredericks Compan') which allowed fur reasonably ac urate readings in the range 1-500 microns. Analytical Methods High-boiling materials (principally dimeric products) were analyzed by gravimetric measurement': in conjunction with nmr analysis employing w-di ni irubenzene (0.0149 M ill CDCl^) as a standard for .roton counting. The procedure for nmr analysis was to disijlve the preV iousl -wei ghed material in 0.5-1.0 ml of the standard

PAGE 124

115 solution recording a minimum of four integral traces for use in calculations. Volatile products were transferred on a vacuum line directly into a nmr tube containing 0.5 ml of the standard solution and analyzed via nmr initially. The volatile products (and CDCl^) were subsequently separated from the m-di ni trobenzene internal standard by vacuumline transferral and analyzed by glpc on column D employing 10.0 yl of either heptane (6.84 mg) or toluene (8.67 mg) as glpc internal standard. 2 4 Static pyrolysis of s;yntri cycl o [4 . 1 . . ' ] hep t a n-5-one tosyl hydra z one sodi urn sal t TjAz^T: initial i soTat i on of 1,2 . 5-cycloheptaTriene dimer (^) and trans1 -ethynyl -2-vi nyl cyclopropane ( 54-t). A sublimation app.iratus was loaded with 0.200 g of Mzl. 3"d immersed in the metal bath heated at 225° (P = -4 \ 5 X 10 mm). A white waxy solid was deposited on the cold finger during the pyrolysis period of 2 hrs. The cold finger was maintained at 0°-9" throughout the period of heating. The sublimation apparatus was removed to the dry box where the white solid was removed with a spatula affording 57.3 mg of the solid with mp 46°-47°. Spectral and elemental analysis of the solid proved che compound to be the head-to-head dimer of 1 , 2 , 5-cycl oheptatri ene : tricyclo [7.5.0.0^'^] tetradeca-4,7,9,12-tetraene (52). This dimer was extremely sensitive to oxygen; an analytical sample of the dimer turned yellow-brown upon exposure to

PAGE 125

116 air after 1 hr. The dimer also proved heat sensitive, turning yellow even in dilute solution upon prolonged heating above 50°. Analysis of the volatile fraction collected afforded a siiull amount of material {% 2,8 mg by nmr only) which, when combined with fractions collected in subsequent pyrolyses, proved to be chiefly ti'ans-^ethynyl-2vinyl cyclopropane (54-t) . Analytical samples of 54-t were obtained by glpc on column D (column 68°, detector and injector 82°, He flow 12 ml/min). Nmr analysis of glpc-purified 54-t indicated that the absence of certain peaks, which appeared in the vinyl and cyclopropyl region of the nmr of crude 5_4, was due to the probable destruction of one isomer ( 54-c ) under glpc conditions. HydrOi^enation of 28.4 mg (1.54 x 10"^ mole) of 52 over 0.200 g of S% platinum (on ca.Don) in 20 nl of ethyl acetate resulted in the uptake of 15.80 ml of hydrogen at 25°/764 mm (theor. 16.90 ml). Mass spectr.il analysis of the hydrogenated product showed the parent peaK of m/ e 192. Tricyclo [Z.l.O.f"^] tetradeca-4 , 7 ,9 , 1 2tetraene : 93% yield; nip 46°-47°; ir ^CCl^, KBr liquid cells): 3020, 2960, 2910, 28b0, 2810, 1650, 1440, 1415, 1360, 1 325, 1235(w), 1215(w), 1190(w), n60(w), 1090, 1070(w), 950, 9jO, 910, 650i nmr (CDLl^): 6 2.33 (m, 4 Hj, 2.3b-2.90 (m overlapped by the two 4 H ni, 2 H), 3.02 (m, 4 H), 5.55 ^m. 6 H) ; uv (ethanol ) ^max '^^^ (^ 8120), shoulders 247

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117 (e 7610) and 263 (e 5500); mass spectrum (m/_e, %): 184 (3.3), 169 (4.2), 156 (2.8), 15b (3.7), 154 (3.1), 153 (2.9), 143 (3.2), 14^ (3.3), 141 (7.9), 130 (6.5), 129 (9.3), 128 (11.7), 127 (3.0), 118 (3.4), 117 (10.5), 116 (5.5), 115 (19.9), 106 (2.7), 105 (7.5), 104 (5.9), 1)3 (5.7), 102 (3.8), 93 (21.8), 92 (22.4), 91 (100.0), 90 (6.0), 89 (10.7), 83 (3.2), 82 (3.4), 80 (5.0), 79 (18.2), 78 (24.3), 77 (41.6), 76 (9.8), 75 (4.8), 74 (3.3) 67 (8.9), 66 (6.3), 65 (32.1), 64 (6.4), 63 (18.6), o2 (4.2), 55 (2.5), 53 (8.1), 52 (7.2), 51 (19.8), 50 ;6.7), 44 (4.2), 41 (19.3), 40 (5.5) , 39 (33.7) , 38 (2.9). Anal . Calcd for C^^H^g: C, 91.25; H, 8.75. Found: C, 91.09; H, 8.76. Trans1 -ethynyl -2vi nyl cyclopropane: 5% yield; ir (NaCl, gas): 3320, 3085, 301U, 2975, 2860(w) , 2120, 1635, 1285, 1245(w), 1190, 1070, 1015, 980, 905, 850(w), 735(w), 635, 600; nmr (100 MHz, CDCl^): 6 0.80-1.40 (m, Hg, Hj, and Hg), 1.85 (d, J^ ^ = 2.0 Hz, H^), 1.58-1.94 (m, H.), and an ABX pattern with multiplets centered at 4.96 (H^), 5.12 (H2), and 5.40 (H^) with J-, 2 " ^^-^ ^^' J, 2 ~ "-5 Hz, J, . = 7.5 Hz, and Jr, = 2.5 Hz; mass spectrum (m/e, %): 92 (100.0), 90 (2.9), 67 (4.2), 66 (17.3), 64 (7.4), 63 (3.0), 53 (5.6), 52 (5.9), 51 (10.1), 50 (6.5), 42 (5.5), 41 (5.1). 40 (5.4), 39 (20.1), 38 (5.4), 37 (3.2).

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118 Anal . Cal cd foi: C 7 8 C, 91 .25; H, ^.75. Found C, 91.11; H, 8.80 2 4 Pyrolysis of s.yn-tri cycl u [ 4 .1.0.0 ' ] heptan-5-one tosyl hydrazone sodium salt: drop-static results . Pyrolytic conversion of 34-s was studied in the temperature range 160°-500° employinn the drop-static technique (D-S) . Typically 0.200 g (6.71 x 10"^ mole) of the salt was added to the heated glass surface at j rate v..:ich would not allow the pressure of the system to exceed 1 mm. At temperatures below 180° decomposition appeared yery slow, making it necessary to extend heating of the salt for 4-7 hrs beyond completion of the addition to insure complete con /ersi on. The results are compiled in Table IV; the results of several static (S^) runs are also included at the bottom of the table. ? 4 Flow pyr o lysis of styntri cycl o [4.1.0.0 ' ] he p tan-5-one tosyl hydrazone sodium sa lt. Flow (F) pyrolysis of 34-s (425".00 ) leJ to the isolation of a product not o!)Sjrved under shorter contact times and at lower temperatures: 4-ethyny 1 -cycl opentene ( 5_5) . Analytically-pure 5_5 was obtained by glpc on column D (column 70", He flow 12 ml/iiiin). Rigorous determination of dimeric material was accomplished only for the case in which the salt was dropped in the "neat" state as opposed

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119 Table IV. Reaction Product Yields from si/n-Tri cycl o [4.1.0.02.4j heptan-^-one Tosyl hydrazone Sodium Salt (0.200 g per run). Techni

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120 to the "diluted" state in which the salt was diluted with either Chromasorb P-Reg or Woelm basic alumina (activity I). The f 1 ow-pyrolys i s results appear in Table V. 4ethynyl-cyc iopentene: ir (NaCl, gas): 3325, 3070, 2940, 2865, 2125, 1620, 1460, 1325, 1250, 1180(w), 1050, 1030, 1010, 935, 910, 765, 745, 690, 625; nmr (CDCl^): 6 2.04 (d, J = 2.0 Hz, acetylenic H), 2.20-3.20 (complex m region, allyl and propargyl H, 5 H), 5.68 (s, olefinic H, 2 H); mass spectrum (m/e, %): 92 (100.0), 90 (^.0), 67 (5.4), 66 (12.8), 64 (7.2), 63 (3.2), 53 (3.1), i2 (7.8), 51 (4.5), 42 (4.5), 41 (4.1), 40 (16.9), 39 (4.6). Anal . Calcd for C^Hg: C, 91.25; II, 8.75. Found: C, 91 .11 ; H, 8.80. Pyro lysis o f anti-tr icyclo [4.1.0.0^'^] heptan-5-one tosyl hydra? jne . )d i u m sal t~( 3 4 a ) . Pyrolysis of 34-a under static conditions at 240° (cold finger: 0°-10°) using 0.200 g (6.71 x 10'^ mole) of the salt afforded 56.3 mg (93% yield) of a whita waxy material, mp 46°~47°, whose nmr, ir, uv, and mass spectra were virtual fingerprints of the dimer (52^) obtained from pyrolysis of 34-s . Nmr analysis of the volatile fraction showed a trace of 54-t (% 1.2 mg , 2%). The results of three drop-sl tc (p_-S^) runs are summarized in Table VI. Elemental analysis of 52^ was satisfactory. Anal . Calcd for C^^H^g: C, 91.25; H, 8.75. Found: C, 91.17; H, 8.78.

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121 Table V. Reaction Product Yields from Flow Pyrolysis of sz/n-Tricyc 1 [4.1.0.02, 4] heptan-5-one Tosylhydrazone Sodium Salt. T Heat, Zone . _ _ . _ °C Path Length %5_2° %54-t^ %5^^ %56^ XSjy 500^'9

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1^2 Table VI. Reaction '''roduct Yields from anti-Tri cycl o [4 . 1 . 0. o2 >^^] heptan-5-one Tosy 1 hydrazone Sodium Salt (0.200 g per run). Techni que* T °C %52 %54-t %55 %56 %57 D-S D-S D-S S 250 300 400 240 90 94 88 93 6.5 2.6 1 .0 «d 2.0 3.0 1.2 3.9 Cold finyer maintained at 0-10°. and nmr analysis. *^Nmr and glpc analysis only. Gravimetric ^Nmr analysis

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123 ,3,0 Pyrolysi s of j.y nand ant^-tr\cyc^o [5.1.0.0 ' J octan-2one tosyl liydrazone sodium salts (5,L^ and 5J_r. J . Investigation of the pyrolytic behavior of the sodium salts 5 1 -s and 51 -a in the temperature range 260"-400° resulted in the isolation of two products which were obtained from the pyrolysis of either salt. The drop-static technique ( D-S ) was used typically employing 0.100 g (3.21 4 X 10 mole) of the respective sodium salt. In the temperature range .60"-385°, e-ts1 -al ly 1 -2-ethynyl -cycl opropane (65) was isolated as the major product with the minor product octa1 ,2 ,5 ,7-tetraene (6j5) increasing in proportion with rise in temperature. At 400° product inersion occurred with 66^ becoming the major product and 6^ the minor product. Separation and purification of 6_5 and 66 was achieved on column D (column 82°, He flow 12 ml/min) with respociive rel ntion time' of 24.8 min and 32.8 min. The results of the pyrolytic conversions of sodium salts 51-s and .' Ij^a are listed in Table VII. CtJ1 -a 1 ly 1 -2ethynyl-cycl. propane: ir (NaCI, gas): 3320, 3080, 3010, 2920, 2850(w), 1825, 1645, 1435, 1340, 1280, 1195, 1035, 990, 910, 740, 635, 600; nmr (CDCI3): 6 0.47 (m, Hg), 1.02 (complex m, H^ and H^,) , 1.38 (complex m, H^), l.bl (d, Jg g = 2.0 Hz, Hj^), 2.23 (m, H^, 2 H), and an ABX pattern with multiplets centered at 5.02 (H3), 5.10 (H^), and 5.95 (H^) with J^ 2 " ^^-^ ^^' '^1 3 " ^-^ ^^' ^"^ ''l 4 " ^'^ ^^'

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124 Table VII Reaction Product Yields from synand antiTricyclo [5.1.0.o3,5] octan-2-one Tosylhydra' zone Sodium Salts (0.100 g per ruii). Sodium Salt

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125 mass spectrum (m/e, %): 106 (2.5), 105 (13.3), 103 (2.7), 93 (3.1), 92 (25.7), 91 (100.0), 89 (2.9), 79 (10.8), 78 (18.0), 77 (9.5), 67 (6.8), 66 (7.7), 65 (29.5), 64 (2.7), 63 (9.5), 62 (4.4), 55 (3.3), 54 (38.2), 53 (8.5), 52 (9.5), 51 (14.3), 50 (8.3), 41 (15.3), 40 (35.5), 39 (44.8), 38 (6.2), 37 (2.7). Anal Calcd for CgH^p C, 90.50; H, 9.50 Found C, 90.30; H, 9.62. Octa-1 ,2,5,7-tetraene: ir (NaCl, ga^); 3090, 3005, 2910, 1955, 1805, 1645(b), 1605, 1435, 1300, 1255, 99o, 910, 845, 740; nmr (100 MHz, CDClJ: 6 2.84 (pseudo h, H3. 2 H), 4.74 (pseudo p, H^ 2 H), 4.94-5.32 (m, H^, H^, and Hg), 5.50-6.60 (m, H^, H^, and Hg); uv (ethanol): ^^=,. 225 (e 2/, 100); mass spectrum {m/±, %): 106 (11.8), max 105 (24.0), 103 (8.0), 92 (7.9), 91 (100.0), 80 (2.9), 79 (27.0), 78 (42.5), 77 (27.9). 67 (37.6), 66 (8.9), 65 (31.3), 63 (7.2), 54 (5.0), 53 (9.1), 52 (10.7), 51 (21.1), 50 (10.7), 41 (51.0), 40 (6.6), 39 (47.5), 38 (6.5). Anal . Calcd for C^H^q: C, 90.50; H, 9.50. Found: C, 90.31 ; H, 9.56. Flow pyr olysis of gts1 -al ly 1 -2-ethynyl -cycl opropane (6j. ) . Flow pyrolysis of 6^ was carried out at 410" under a controlled vacuum of 0.02-0.40 mm. The cyclopropane (0.0262 g, 2.47 x 10" mole) was placed in an open-ended

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126 capillary which was then set inside the solid uduition apparatus previoui^ly described for the controlled addition of solids. The loading procedure was carried out under nitrogen in the dry box. The cyclopropane was subsequently allowed to slowly bleed through the pyrolysis region (40 cm heat zone) by careful control of the Rotaflo stopcock vaporization and pyrolysis of ^ being completed within five min, Nmr inspection and glpc analysis (column D) of the pyrolysate showed no trace of starting material. The only identifiable proiuct was octa1 ,2 , 5 , 7te traene ( 6b) which was formed in 72% yield: 0.0190 g, 1.79 x 10"^ mole. Uv inspection showed only the characteristic absorption at 225 nm (t 27,100) obtained al'>o for the ortatetraene product isolated previously f r urn the tosylhydrazone sodium salt pyrolyses. Pyrolysis of tr ana-l-eth yny l -2-vi nyl -cycl opropane (54-tJ _ . The trans cyclopropane (54 t) (0.0141 g, 1.53 x ,-4 10" mole) was placed in 0.5 ml of deuteroch 1 orof O' m in an ordinary nmr tube. The solution was degassed (five times) and the tul^e sealed. The tube was subsequently heated at 100 + 2° in u well-stirred kinetic oil bath for 198 min (3.30 hrs) without any change in the nmr spectrum of the starting material. Heating at 169 + 3° for 137 min (2.28 hrs) produced no change also. The cyclopropane was

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127 separated from the deuterochl oroform via glpc (column D) and pldced in 0.5 ml of benzene-d, in order to avoid possible acid-catalyzed reactions at higher temperatures {> 169"). The benzene-d, solution (10 yl benzene: nmr internal standard) was placed in a thick-wall nmr tube and was degassed and sealed as before. The nmr tube was placed inside a thickwall glass sleeve containing benzene in a volumetric amount proportional to the benzene-dg volume within the sealed nmr tube. This was done so as to maintain '^' equal pressures inside and outside the sealed nmr tube. The glass sleeve was sealed under vacuum and the cyclopropane subjected to heating at ^08 + 2° for 128 min (2.13 hrs). Nmr inspection showed that the cyclopropane had quantitatively converted to the 1,2,5-cycloheptatriene dimer ( 5^_) . Verification of this fact was supplied by uv and mass spectral analysis which supplied spectra which were fingerprints of dimer 5J^ obtained directly from the pyrolysis of ei ther .< jnor antt-tri cyclo [4.1.0.0 '] heptan-5-one tosyl hydrazone sodium salts. 2 4 Pyrolysis of s.yn-tricycl o [4.1.0.0 ' ] heptan-5-one tosyl hydrazo n e sodium salt inthe presence of styrene: 135 and 210 . The sodium salt (0.200 g, 6.71 x 10"^ mole) of si/n-32 was placed in a 3-oz Fisher-Porter Aerosol Compati bility tube employing 20 ml of diglyme (distilled from

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128 CaHp and stored over CaH^ under nitrogen) as reaction solvent. Styrene (3.60 g, 0.0346 mole) was introduced after having first removed the stabilizer by chromatography on Woelm basic alumina (activity I). The charged tube (n-gnetic stirrer included) v/^s immersed in a G.E.-S.F.-97 oil bath heated at 135 + 3° for 153 min (2.55 hrs). The volume of evol 'ed nitrogen was determined upon cooling of the reaction mixture to 25°: 12.60 ml (16.25 ml Iheor.), 78%. The reaction mixture was filtered md the mixture diluted wit^l 20 ml of HpO. Extraction of the aqueous diglyme solution with 80 ml of pentane afforded a pentane extract from which a white solid (polystyrene) precipitated. The pentane layer was filtered several times to remove precipitating polystyrene and finally washed with two 20-ml aliquots of HpO. The pentane layer was dried over Na^SO, and concentrated by rotary evaporation affordinr a slightly colored liquid residue. Excess styrene was removed at 3-10 mm leaving a residue (oil-solid mixture) which was diluted with 100 ml pentane, filtered again several times to remove polystyrene, an 1 worked up with H^O as before. Drying and concentration in voauo affordrd a residue which was suitable for prepara ive layer chromatography (silica gel). One eljtion with pentane afforded a broad fast-moving band (R^ = 0.71) which was subsequently exposed to the atmosphere for a period of ^y5 days. The band (now colored)

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129 was t echroniatographed using three elutions with pentanG. The fastest-moving band (R^ = 0.75) afrorded 0.0344 g (1.76 X 10" mole, 26%) of 2-phenyl -spi ro [eye 1 opropane1 ,5'w/n-tricyclo [4.1.0.0^''^] heptane] (61) which, by nmr spectral inspection, appeared to be a mixture of the two possible isomers. Tht trapping reaction was repeated at 210 + 3° employing 0.?0' g (6.71 x IC"'^ mole) of the sodium salt, 20 ml of tetraglyme (refluxt-U over and distilled ' rom CaH2), and 6.99 g (0.0672 mole) of styrene (sal t-styrene •'ati. 1:100 as opposeti to 1:50 in the first run). The reiction mixture was heated for a period of 83 min (1.38 hr). i he volume of nitrogen evolved measured 13.90 ml (16.25 ml theor.), 86%. Workup as before and preparative layer chromatography afforded 0.0453 g (2.31 x 10" mole) of 61 (isomeric mixture): 34% yield. 2 4 2-phenyl -spi ro [cycl opropane-1 ,5 ' -s^n-tri cycl o [4.1.0.0 ' ] heptane]: ir ^ Cl^, KBr liquid cells): 3070, 3040, 3010, 1605, 1500, 1465, 1265, 1095, 1070, 1040, 1025, 905, 865, 700(s); nmr (CDCI3): 6 -0.05-0.73 (complex m, 4 H) 0.75-1.93 (complex m, 4 H), 1.25 (d, 7.5 Hz, 2 H), 2.15 and 2.30 (ovf^rl appi ng t, 7.5 and 7.0 Hz, respectively, 1 H), 7.18 (d, 5 H); uv (ethanol): X _ 276 (c 378), 267 (e 527), max 262 (e 527), 226 (e 7490); mass spectrum (m/e^, %): 196 (8.2), 181 (12.1), 168 (10.9), 167 (17.1), 166 (9.7), 165 (13.2), 155 (18.1), 153 (10.0), 149 (16.3), 142 (27.5), 141

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130 (26.3), 130 (9.1), 129 (25.6), 128 (20.9), 118 (20.0), 117 (28.4), 116 (10.6), 115 (25.0), 106 (15.0), 105 (88.5), 104 (32.5), 103 (23.8), 93 (9.4), 92 (65.0), 91 (100.0), 89 (12.5), 83 (8.5), 79 (31.3), 78 (20.6), 77 (40.0), 65 (23.8), 63 (14.4), 58 (35.0), 57 (9.7), 55 (8.8), 53 (8.4), 52 (8.8), 51 (26.3), 50 (9.4), 43 (82.)), 41 (22.2), 39 (34.4). Anal . Calcd for C^^H^g: C, 91.78; H, 8.22. Found: C, 91.65; H, 8.27. 2 4 Pyro l ysis of s.yn-t r ic.yclo [4 .1.0.0 * ] hepta n-5-one tosy lhydrazone sodium It in the presence o f dimethyl maleate : 210°. The sodium salt (0.2u0 g, 6.71 a 10' mo i e ) of syn-33_ was placed in a 3-oz Fi sht-r-Porter Aerosol Compatibility tube employing 20 ml of anhydrous tetraglyme as reaction solvent. Dimethyl maleate (> 99% pure by glpc analysis after chromatography on silica gel 60-Merck) was introduced as a 100-fold excess of trapping agent: 9.69 g (0.0672 mole). The charged tube (magnetic stirrer included) was immersed in the G.E.-S.F.-97 oil bath heated at 210 _+ 3° for 83 minutes (1.38 hr). Upon cooling the dark reaction mixture to 25°, the volume of evolved nitrogen was determined: 8.75 ml (16.25 nil theor.), 54%. The tetraglyme solution was diluted with 80 ml of H^O and extracted with 200 ml of pentane. The pentane layer was filtered

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131 free of a white solid (dimethyl fumarate) and washed with five 50-ml aliquots of HpO. The pentane layer was dried over NapSO« and concentrated by rotary evaporation. The moist white solid obtained was 1 irgely di' -thy! fumarate (via i someri zati on of dimethyl maleate under the reaction conditions employed). The solid material was carefully triturated with 30 ml of pet ether (low boiling) followed by trituration with 30 ml of pt tane. The residue obtained by concentration of the pet etner-pe,. t. ;te tri curate was largely the fumarate but suitable for preparative layer chromatography (silica gel). Three elutions with hexane afforded a broad slow-moving band (R^ = 0.3^^' which was rechromati rai'hed using four elutions with benzene. Two closely spaced bands (kr. = 0.60 and 0.53, respectively) were obtained, the large slower-moving bam beiig chiefly dimethyl fumarate. The f a-jti;r-movi ig band ( 0. ' 51 4g, 2 . 60 X 10' luole, 39% yield) proved to be the carbene adduct, /;rans-2 , 3-di carbomethoxy-spi ro [cycl opropane1 ,b'-ai/«tricyclo [4.1.0.0^'^] heptane] (62): mp 72°-74°; ir (CCl^, KBr liquid cells): 3080, 3040, 3010, 2950, 29:';), 2&--U, 1740(s), 1455, 1440(s), 1360, 1340(s), l?90(s), 1260, 1230(s), 1195, 1165(s), 1095, 1070, 135, 1015, 900, 870, 830, 695, 670, 660; nmi (CDCl^): 6 0.52 (m, 4 H), 1.70 (m, 4 H), 2.42 (d, 5.8 Hz, part of ABq, 1 H), 2.65 (d, 5.8 Hz, part of ABq, 1 H), 3.72 (s, 3 H), 3.76 (s, 3 H); mass spectrum (m/e, %): 236 (< 1.0), 204 (4.0), 178 (F )),

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132 177 (31.3). 1/6 (12.7), 174 (5.4), 161 (7.4), 149 (6.9). 146 (9.6), 145 (66.0), 144 ( " 8", 135 ^^.1), 134 (6.6), 131 (7.4). 127 (9.1), 121 (4.2), 119 (6.3;, 118 (16.5), 117 (100.0;, 116 (32.4), 115 (46.6), 113 (16.9), 105 (10.9), 104 (7.5), 103 (11.0), 1U2 (4.1), 99 (18. S), 9. (22.3), 91 (84.5), 90 (4.6). 89 (7.5), 85 (8.0), ^9 (23.6), 78 (10.8), 77 (19.4), 71 (8.4), 69 (6.6), 67 (4.6). 66 (6.9), 65 (23.9), 64 (4.0), 63 (11.0), 59 (31.2), 58 (4.9). 57 (9.5), 56 (5.2), 55 (13.6), 54 (4.0), 53 (12.7), 52 (8.9), 51 (18.3), 50 (7.4), 45 (10.1), 44 (30. L), 43 (10.8), 42 (5.3), 41 (27.4), 40 (9.5), 39 (3b. 8), 38 (6.6), :o (4.9). Anal . Calcd fo^ C^3H^g0^: C, 66.09; H, 6.83. Found: C, 66.01 ; H, 6.85. At tempt e d^ l_o w-te m i . ern ture i sol at i on of key in t ermediates in' the py r oly si s yf jjz/n^tri c ycl o"7T ' ~i • • 0^^ J~hepta ri -5one tosy 1 hydrazone .>o d i urn salt . Tne low-temperature isolation an t (see loutnote on page 50) employed for the attempted trapping of key intermediates in the pyrolysis of syn-33 sodium salt was designed and built with the capacity for e sily interchangeable optics to facilitate inspection of b-th the uv-visible and the ir regiois of interest. for infrared work, cesium iodide (Csl) ootics were generally emplo/ed; spectra were recorded by a Perkin-Elmer Model 621 Infrared Spectrometer. Ultraviolet-visible work was

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133 performed with the use of calcium fluoride (CaF„) optics; spectra were recorded by a Jarrel-Ash ultraviolet sensorphotomul ti pi i er-recorder system (ultraviolet source: deuterium lamp; visible source: tungsten lamp). Typically 5 mm of argon was first deposited on the matrix window (at 6°K) while maintaining a dewar iressure in the range 1.5 X 10" 4.2 X 10' mm. Employing the drop-static technique ( D-S ) , the sodium salt was then pyrolyzed at 250° in a glass vessel (without a cold finger). The volatile pyrolysate was fed by a 19 cm glass connector to the matrix window. The amount of sodium salt pyrolyzed was in the range 0.075-0.100 g (2.52 x 10"^ 3.3o x 10"^ mole). Controlled dropping of the salt was effected by the use of an ion gauge which effectively monitored nitrogen evolution; the maximum pressure of the system at any time was observed to be 9.0 x 10" mm. At completion of the pyrolysis, 22-25 mm of argon was observed to have been delivered to the matrix window during the period of pyrolysis. Matrices generated in this manner were generally well-set except for minor "bubbling" at the center of the matrix window. Uv-visible inspection of the matrix in the range 200-500 nm showed only very strong absorption in the 254 nm region characteristic of the 1,2,5-cycloheptatriene dimer (5^). Ir inspection was more informative although it appeared most absorptions were due to the

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134 presence of 1 -ethynyl -2vi nyl cyclopropane ( 54-t and/or 54-c ) and the dimer (52^). The following absorptions were recorded in the ir region 200-4000 cm" (50-2.5 y): 3305 (s). 3080, 3005, 2905, 2845, 2795, 2125, 2043, 2035 (shoulder), 1633, 1600(b), 1437, 1405, 1355(w), 1345, 1285(w), 1270(w), 1208(w), 1183, 1100, 1090, 1078, 1065. 1035, 1015, 1003, 980, 953, 943(w), 923, 915, 893(s), 868, 845, 780, 770, 750, 725, 703, 685, 645(s), 637(s), 620, 588, 500, 485, 363, 343, 323, 310, 295. The nature of the absorption at 2043 cm' with a shoulder at 2035 cm" was of principal interest ( 1 ,2 , 5-cycl oheptatri ene ?) although the absorption might easily be accounted for by the sz;n-5-diazo-tricyclo [4.1.0.0 ' ] heptane species (51). However, no uv X was readily observed for 59 although max the concentration and expected mall extinrtion coefficient (e 10) of 51 may have combir'ed to give an absorption of negligible intensity which was lost in baseline noise. The two stronger, ir absorptions at 33i)5 and 893 cm" were apparently due to cycl ot-i opanes 5j4. 2 4 Generation of synand g/tti5Jiazotri cycl o [4.1.0.0 ] heptane s ( 59.) : i sol at i on of u'-z^s-l -ethynyl -2vi nyl -cyc l opropane (54-cy ! Static pyrolysis (S_) of 0.400 g (0.0134 mole) of either 34-s or 34-a , maintaining a cold finger temperature of -72° to -65°C while raising the metal bath temperature

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135 from 140°-225° over a period of 30 min, afforded observation of a red liquid condensed on ttie cold finger. Even at these low temperatures, it appeared that the red liquid, synor 2 4 anti-S-di azo-tricycl [4.1.0.0 ' ] heptane (5^), slowly lost nitrogen (perhaps photochemistry induced) as evidenced by the gradual "bubbl i ng-up" of the material deposited on the cold finger accompanied by dissipation of the rod color of the condensate. The pyrolysis period was arbitrarily for 60-90 min at which point the nietal bath was removed. The cold finger was maintained at low temperatures for 30-45 min longer at which time the cold finger was allowed to warm to 25°. The nonvolatile material left behind on the cold finger after disappearance of the red color attributed to the respective diazo compounds was a deep yellow in color. Nmr inspection showed the yellow material to be a complex mixture of dimer (52) and largely unidentifiable products showing broad absorptions in the rogion 6 0,2-2.65. Ir inspection showed a sharp absorption of moderate intensity at 1645 cm which might have been indicative of the presence of Lricyclic heptan-5-one azine material, The results of two pyrolysis runs showed the various nonvolatiles to have forned in ca, 58-65% yield via gravimetric analysis. Examination of the volatile material from both runs afforded the isolation of cis-1 ethynyl -2vi nyl cyclopropane ( 54-c ) as well as cycl oheptatri ene (^6) and tpana1 -ethynyl -2-vinyl -cyclopropane (5 4-t ) in the amounts

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136 specified in Table VIII. The ais compound 54-c demonstrated unusual reactivity, rearranging quantitatively to afford dimer 5^ upon nmr spectral inspection after 36 hrs at 25°. A rough attempt via ninr at determination of the half-life of 54-c at 25° (concentration: -^^ 0.35 M in deuterochl oroform) placed t-. ,p (for a rate-determining unimolecular process) at 2.8 hrs although within experimental error it would be more appropriate to place the figure between two and three hrs. Mass spectral analysis showed the parent peak at m/_e 92 (40.9% vs. 100% for 54-t) al though the spectrum obtained was largely a fingerprint of dimer 5_2 (base peak m/e 91, 100.0%) due to probable pyi )lysis fo 54-c in the tip of the syringe used for mass spectr 1 injection. Cis1 -ethyny 1 -2vi ny 1 -cycl opropane ( 5^^:iC ) : ir (principal peaks only, CDCU, Klir liquid cell): 3310, 3085, 2120, 1635, 985, 600; nmr (100 MHz, CDCl^): 6 0.78 (m, H^), 1.20 (m, H7), 1.48-1.84 (m, H^ and Hg), 1.88 (d, J5 5 = 2.0 Hz), and an ABX pattern with multiplets centered at 5.10 (H3), 5.24 (H^), and 5.64 (H^) witli J^ 2 " ^^-^ ^^ ' J^ 3 = 8.5 Hz, J.| 4 = 7.5 Hz, and ^33" ?-5Hz. It should be n-ted that spectroscopic work (ir and nmr) was complicated by the presence of cycl oheptatriene and the growth of dimer 5_2 via the facile rearrangement of 54-c at 25°.

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137 Table VIII Volatile Product Yields from Static Pyrolysis of si/71and ant£-Tricycl o [4.1.0.02,4] heptan5-one Tosyl hydrazfine Sodium Salts: 140°->-225° Sodi.im^'^ Sal c 54-c 54-t' 56' 34-s 17 34-s 16 34-a 23 g of the i nternal 'Cold finger maintained at -73° to -65°. 0.400 salts. ^Nmr standard . analysis only; benzene (8.7 mg)

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APPENDIX NMR AND IR SPECTRA OF RELEVANT COMPCjNDS

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139 to I (XI c o I I c +J Q. 01 (N) O O >^ u •M •*-» I -o c — to ri. •
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140 n3 I CM c o I I a. CVJ c o

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141 en o I I c o o ir> o o un I to a X en I < 3 CD

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142 I c o I 1 e 4.1 O O n CO o o o I 1= ! s-

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143 I ro CO (U c o N » o !-> o I Uf) I c rO 4-> Cl. (U >ijCM o o u U I eg E in I a: 3

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144 ro I 00 CO 0) sz o rsi to i•o >1 o 4-> 0) c: o I in i s= (O +-> CL o o >> 'r•-> I a E I (U Scn

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45 oi c o IS! •a >> to o 4-J a> o I I c 4-> u o If) CO i-rt u >, o u I (0 o I <: a. i cn

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145 o c o ra io >> -E >i to O +J o o CO o U*) CI. o u O O U I I 4J <3' o o. a) CO I
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147 I E n •f— o o v> to I CO CO >> o o a a) c •r* n3 4J X) o evil m| 0) B I C7>

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148 ra (/) E •r-o O 1/1 I/) I CO O 1/) •r(/1 >> I—" o i. >^ a. B o •a •J— +J o to s. E o I D.

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149 c: ^ u I >4 c >> x: -» 0) I o E I Qi (3

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150 1 dj O I— U C i-J I dj 4-> • ns •) t> o x: LfJ 4-! t— cv X -~> •C 4-> 2 •r03 > Ol I -a QJ CM QJ OJ 1 C :; 1 — -rtri >> E C (O >, X Ci. J= Ol u m i/j o > t: o r— O O Q cn s; > Ja. 3 o o a. o t. E r-D.TCM I «=c scn 'f t

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151 1

PAGE 161

152 3O — O ,>-O O-i . , i

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153 U3 0) sz Q. o SQ. o f— (J >> u >1 c: (U I I I I 6 m I a* scn -1-2-1 -8-

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154 VT'l (U c 0) s. I IT) I (O 4-> U o «o B I 0) L|_si_2_5_

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155

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156 I (U LTl I C + u. x: CVJ O O U >> o iI o CO I < s~ 3 )MVillWSNVHl

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157

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158 I c o I I c +J o o un o til >) o •r" S»-> I -w S a MO o sen {^l g-JNVl.inVSr.'VMi

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159 o o o 1 1 1 1 1

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160 C o N >> O o I in I c CO +J O, OJ o o u >> o i•M I <3

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161 c i 1 p M>

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162 c • o N «0 so >1 (/> o t-> O) IT O I CJ I c «-> u o to O LO o

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163 10 o I/) 1/1 I •^ >) o i. >s tx s o 1. u a> s•o c •rto +J o in u 0) E o in cvj I •a:
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164 — 1 I _ I ' £ •r-o O CI fO CO O >> r— • o ex e o o
PAGE 174

165 « .—

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i66 fcz!zBH"-t t — h -r1 1 a 1. c a. o s_ p. o u >> u I >> C •r> I I >> c I I CO K C o 00 CM I
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167 ^^ _.L_ 3: 0) 4-> e O (J o I aj

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168 r-

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169 (U c (O a. o i. o. o u u I >> c > I CM I
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170 W3 c OJ ro I. 4-> CD •4-> r^ m CVJ I o o O

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REFERENCES 1. M. Jones, Jr. and R.A. Moss, "Carbenes," Vol. 1, John Wiley and Sons, Inc., New York, N.Y., 1973; and references cited therein. 2. W. Kirmse, "Carbene Chemistry," 2nd ed., Academic Press, New York, N.Y., 1971; and references cited therein. 3. H. Olirt ind F. Werndorff, Anqew. Chem. Int. Ed . , ]_, 4 (19,4). 4. L.W. Christensen, E.E. Waali, and W.M. Jones, J. Amer . Chem. Soc . , 9^, 2118 (19 '2). 5. R. Gleiter and R. Hoffman, ibid., 90, 5457 (1968). 6. E. Wasserman, L. Barash, A.M. Trozzolo, R.W. Murray, and W.A. Yager, ibid ., 86, 2304 (1964). 7. H. DLirr, Fortschr. Chem. Forsth ., 40, 103 (1973). 8. a. R.A. Moss, J. Org. Chem ., 31, 3296 (1966). b. R.A. Moss and J.R. Pryzbyla, ibid . , 33^, 3816 (1968). 9. P.B. Shevlin and A. P. Wolf, Tetrahedron Lett . , 3987 (1970). 10. R.G. Bergman and V.J. Ra jadhyaksha , J. Amer. Chem. Soc , 92, 2i63 (1970). 11. For reviews of Cope rearrangements, see: E. Vogel , Angew. Chem. Int. Ed ., 2, 11 (1963); W. von E. Doering and W.R. Roth, ibid ., 2, 115 (1963). 12. S. Winstein, Qu art. Rev. Chem. Soc . , 23^, 141 (1969). 13. R.D. Gilliam, "Introduction to Physical Organic Chemistry," Addison-Wesley , Inc., Reading, Massachusetts, 1970. 14. a. W.J. Ball and S.R. Landor, J. Chem. Soc , 2298 (1962). 171

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172 b. W.R. Moo> e and W.R, Moser, J . A mer . Chem Soc . , 92, 5469 (1070). 15. a. W.R. Moore and W.R. Moser, J. Org. Chem . , 35 , 908 (1970). b. G. Wittig and P. Fritze, Angew. Chem. Int. Ed . , 13, 846 (1974). 16. M. Christ! and G. Bruntrup, Ibid ., U, 208 (1974). 17. G.M. Kaufman, J. A. Smith, G.G. Vanr'er Stauw, and H, Srhecter, J. Amer. Chem. Soc . , 87 , 935 (1965). 18. L.L. f^iiier and J.R. Joinso.-i, J . Org. Chem . , 1, 135 (1936). 19. ii.P. Drey fuss, ibid . , 2_8, 3269 (1963). 20. a. E.C. Horning, Ed., "Organic Syntheses," Coll. Vol. 3, John Wiley and Sons, Inc., New York, N.Y., 1967, pp. 482-483. b. M.C. Lasne and M.A. Thuillier, Comptes rendus , 273 1253 (1971). 21. J.J. Gajewski and C.C. Shih, Tetr ahedron Lett . , 2967 (1970). 22. A.P.TerBorg and H. Kl oosterzi el , Rec . trav. chim . , 82 , 1189 (19b3). 23. W. von £. Doering, E.T. Fosse! , and R.L. Kaye, Tetra hedron, 2_1 , 25 (1965). 24. M.M. Fawzi and CD. Gutsche, J. Org. Chem ., 3J,, 1390, (19 6). 25. E. Vogel , R. Erb, G. Lenz, and A. A. Bothner-By, Justus L iebigs Ann. Chem . , 682 , 1 (1965). 26. N.A. Nelson and G.A. Mortimer, J. Org. Chem., 22, 1146 (r'57). — 27. .A. Russel, J.J. McDonnell, P.R. Whittle, R.S. Givens, and R.G. Keske, J. Amer. Chem. Soc , 9^, 1942 (1971). 28. G.A. Russel and G.R. Stevenson, ibid ., 92, 2432 (1971). 29. W. Kirmse and L. Ruetz, Justus Liebigs Ann. Chem ., 726 30 (1969).

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173 30. J.B. Lambert, F.R. Koeng, and J.W. Hamersa, J . Org. Chem . , 26, 241 (1971). 31. a. J. Briggs, F.A. Hart, and G.P. Moss, Ch em. Comm . , 1^^. 1506. b. M.R. Willcott, R.E. Lenkinski, and R.E. Davi'^, J_. Amer. Chem. So ., 94, W42 (1972). c. M.R. Willcott and R.E. Davis, ibid ., £4, 1744 (1972). 32. N. Hasty, Jr., Ph. D. Thesis, University of Wisconsin, 1970. Also private communication from Dr. J. A. Berson, L-^partment of Chemistry, Yale University, New Haven, Connecticut. 33. T.A. Antkowiak, D.C. Sanders, G.B. Triniitsis, J.B. Press, and H. Schecter, J. A me r. Chem. Soc . , 94 , 5366 (1972,. 34. K.G. Untrh and D.J. Martin, J_bj_d . , 87, 4501 (1965). 35. J.M. Brown, B.T. Goldinq, and J.J. Stofko, Che m. Comm . , 1973, 319. 36. M. D'Amore, Ph. D. Thesis, California Institute of Technology, 1972. 37. S.J. C) istol and J.K. Harrington, J . Org . Chem . , 28 1413 '1963). 38. H.M. Enssliw and M. Hanack, Angew. Chem. Int. Ed., 6, 702 (1967). 39. a. G. Schrumpf, Tetrahedron Lett . , 2571 (1970). b. S.A. Sherrod and R.G. Beraman, J . Amer . Chem. Soc . , 93, 1925 (1971). 40. H. Weitkamp, U. Hasserodt, and F. Korte, Chem. Ber . , 95, 2280 (1962). 41. D.J. Patel, M.E.H. Howden, and J.D. Roberts, J. Amer . Ch em. Soc , 85^, 3218 (1963). 42. T. Shono, T. Morikawa, A. Oku, and R. Oda , Tetrahedron Lett. , 2967 (1967). 43. W.D. Huntsman, J. A. DeBoer, M.H. Woosley, J. Amer. Chem . Soc. , 88, 5846 (1966).

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174 44. E.E. Eliel, "Stereochemistry of Carbon Compounds," McGraw-Hill, Inc., New York, N.Y., 1962, pp. 330-333. 45. W.G. Woods, J. Org. Chem . , 2^, 110 (1958). 46. T. Sasaki, S. Eguchi, M. Ohno, and T. Umemura, J . Org . Chem . , 38, 409 5 (19,3). 47. R.B. Woodward and R, Hoffman, "The Conservation of Orbital Syiiimt-try , " Verlag Chemie, Weinheim, Germany, 1970. 48. A. Strei twei ser , Jr., and R.W. Taft, Ed., "Progress in Physical Organic Chemistry," Vol. 9, Wi 1 ey-Interscience , New York, N.Y., 1972, pp. 34-35, 47-48. 49. H.E. Zimmerman, Accts. of Ch em. Res . , 4, 272 (1971). 50. a. K, Fukui, Fors chr. Chem. Forsch ., 1_5 , 1 (1970). b. K. Fukui and H. Fujimoto, "hechanisms of Molecular Migrations," Vol. 2, B.S. Thyagrarjan, Ed., Interscience, New York, N.Y. 1969. c. K. Fukui, Accts. of Chem. Res . . 4, 57 (1971). 51. F. Jones, Jr., S.R. Reich, and L.T. Scott, J. Amer . C em. Soc , 92^, 3118 (1970). 52. H.E. Zimmerman and L.R. Sousa, ibid . , 94 , 834 (1972). 53. L. Skattebol and S. Solomon, ibid ., 87^, 4506 (1965). 54. P.W. Dillon and G.R. Underwood, ibid ., 96, 779 (1974). 55. S. Benson, F.R, Cruickshank, D.M. Golden, G.R. Haugen, H.E. O'Neal, A.S. Rodqers, R. Shaw, and R. Walsh, Chem. Re v., 69_, 2 79 (1969). 56. C. Wentrup, Tetrahedron , 30, 1301 (1974). 57. W.R. Dolbier, Jr., "Cyclic All enes: 1 , 2 , 5Cycloheptatriene — Structure and Reactivity," Research Proposal submitted to the National Science Foundation by the University of Florida, Gainesville, Florida, April 1975. 58. V. Dalacker and H. Hopf, Tetrahedron Lett . , 15 (1974). 59. H.E. Zimmerman, Accts. of Chem. Res . , 5, 39 3 (1972).

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175 60. W.M. Jones and U.H. Brinker in "Pericyclic Reactions," A. P. Marchand and R.E. Lehr, Ed., Ac?'^emic Press, New York, N.Y., in press. 61. N. Rabjohn, Ed,, "Organic Syntheses," Coll. Vol. 4, John Wiley and Sons, Inc., New York, N.Y., pp. 424-426. 62. R.S. Monson, "Advanced Organic Synthesis," Academic Press, New York, N.Y., 1971, pp. 155-156. 63. E. LeGoff, J. Org Chem. , 2_9 , 2048-9 (1964). 64. L.F. Fieser and M. Fieser, "Reagents for Organic Synthesis," Vol. 1, John Wiley and l^ons, Inc., New York, N.Y., 1967, p. 142.

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BIOGRAPHICAL SKETCH Oscar Trinidad Garza was born in Jacksonville, Florida on January 14, 1947. He attended the Assumption and Christ the Kiny Catholic parochial schools in Jacksonville for his elementary education. The first two years of high school were spent at the Josephinum High School in Worthington, Ohio, the final two at Bishop Kenny Catholic High in Jacksonville. After graduation from high school he attended Jacksonville University from 1965-1969 on a President's Scholarship, graduating cum laude in August 1969. He immediately enrolled at the University of Florida in order to pursue graduate studies in chemistry, the culmination of which is the preparation of this dissertation. He married the former Mary Jane Champion and, after five years of marriage, they were blessed with a fine son, Austin Edward. Together they will head north to Wilminiton, Delaware ^o become part of the Dupont working family. 176

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I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. /^ (likv^L /M&CY I -hWilliam R. Dolbier, Jr., Chairman Associate Professor Of Chemistry I certify that I have read this study and that in my r'pinion it conforms to acceptable standards of scholarly presentation and is fully adciuate, in scope and quality, as a dis-^ertati on for the degree of Doctor of Philosophy. J^anies A. Devrup, ;'' i/ Professor of Ch^mistiy #^1 I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. ]oL. (X2j±x..^ ihn A. Zol tewi cz Professor of Chemistry

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I certify that I have read this sti'dy and that in my opinion it conforms to accepiable standirds of scholaHy presentation and is fully adequate, in 3^ opr^ atid quality, as a dissertation for the deg' ee of Hoctor of Philosophy. J-A. 1 1 1 i am Wei r r rf e s s r Id Jlft^^ t n e r , Jr. f Chemistry I certify that I have read this study and that in my opinion it conform^ to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. Ja^es L' . Keesling 7 sociate Professor of Mathematics This dissertation was submitted to the Graduate Faculty of the Departmtnt of Chemistry in the College of Arts and Sciences and to the Graduate Council, and was accepted as partia"^ fulfillment of the requirements for the degree of Doc to i of Philosophy. August, 1975 Dean, Graduate School

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yf i^j^i. o OU. tt i5ff -^^ ,v ^d(i!D