• TABLE OF CONTENTS
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 Title Page
 Dedication
 Acknowledgement
 Table of Contents
 List of Tables
 List of Figures
 Abstract
 Introduction and background
 Results
 Discussion
 Experimental
 References
 Biographical sketch














Title: Carbene-carbene rearrangements
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 Material Information
Title: Carbene-carbene rearrangements a study in the benzocycloheptatrienylidene-naphthylcarbene system
Alternate Title: Benzocycloheptatrienylidene-naphthycarbene system
Physical Description: xii, 92 leaves. : illus. ; 28 cm.
Language: English
Creator: Krajca, Kenneth Edward, 1944-
Publication Date: 1972
Copyright Date: 1972
 Subjects
Subject: Carbenes (Methylene compounds)   ( lcsh )
Chemistry thesis Ph. D
Dissertations, Academic -- Chemistry -- UF
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Thesis: Thesis -- University of Florida.
Bibliography: Bibliography: leaves 87-91.
Additional Physical Form: Also available on World Wide Web
General Note: Typescript.
General Note: Vita.
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Bibliographic ID: UF00097621
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: alephbibnum - 000577359
oclc - 13958996
notis - ADA5054

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Table of Contents
    Title Page
        Page i
        Page i-a
    Dedication
        Page ii
    Acknowledgement
        Page iii
    Table of Contents
        Page iv
        Page v
        Page vi
        Page vii
        Page viii
    List of Tables
        Page ix
    List of Figures
        Page x
    Abstract
        Page xi
        Page xii
    Introduction and background
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
    Results
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
    Discussion
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
        Page 54
        Page 55
        Page 56
    Experimental
        Page 57
        Page 58
        Page 59
        Page 60
        Page 61
        Page 62
        Page 63
        Page 64
        Page 65
        Page 66
        Page 67
        Page 68
        Page 69
        Page 70
        Page 71
        Page 72
        Page 73
        Page 74
        Page 75
        Page 76
        Page 77
        Page 78
        Page 79
        Page 80
        Page 81
        Page 82
        Page 83
        Page 84
        Page 85
        Page 86
    References
        Page 87
        Page 88
        Page 89
        Page 90
        Page 91
    Biographical sketch
        Page 92
        Page 93
        Page 94
        Page 95
Full Text

















CARBENE-CARBENE REARRANGEMENTS: A STUDY IN THE
BENZOCYCLOHEPTATRIENYLIDENE-NAPHTHYLCARBENE SYSTEM








By





KENNETH EDWARD KRAJCA


A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF
THE UNIVERSITY OF FLORIDA IN PARTIAL
FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY


UNIVERSITY OF FLORIDA
1972










DEDICATION

This dissertation is dedicated to the author's wife,

Sherry Lee, whose work, understanding, and love made this

work possible and to his daughter, Laura, who provided him

with much happiness.











ACKNOWLEDGMENTS

The author is indebted to Dr. W. M. Jones for his

professional guidance, patience, and personal friendship

during the course of this work. His advice and encourage-

ment will be of lasting benefit. The counsel and discussion

of the author's fellow associates are highly regarded.

The author wishes to thank his parents for their

guidance and help.

Finally, the author wishes to thank the Petroleum

Research Fund and the National Science Foundation for

providing financial assistance during this period of study.











TABLE OF CONTENTS


ACKNOWLEDGMENTS ... .................................. .

LIST OF TABLES........................................

LIST OF FIGURES ... ....................................

ABSTRACT .............................................

CHAPTER

I. INTRODUCTION AND BACKGROUND....................

II. RESULTS ........................................

III. DISCUSSION......................................

IV. EXPERIMENTAL ...................................

General. .....................................

Pyrolysis of the Sodium Salt of Benzaldehyde

Tosylhydrazone in Diglyme.............

Pyrolysis of the Sodium Salt of Tropone

Tosylhhyrazone in Diglyme ............

4,5-Benzotropone ...........................

4,5-Benzotropone Tosylhydrazone ...........

B-Naphthaldehyde Tosylhydrazone...........

General Preparation of the Sodium Salt of

Tosylhydrazones ......................

Pyrolysis of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone in Diglyme.....









Photolysis of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone in Diglyme..... 62

Pyrolysis of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone in Benzene..... 63

Photolysis of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone in Benzene..... 64

Preparation of 2-naphthaldazine ............ 64

Pyrolysis of the Sodium Salt of 8-Naphth-

aldehyde Tosylhydrazone in Cyclohexene. 64

Pyrolysis of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone in Cyclohexene

at 83 ..................................... 66

Pyrolysis of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone in Cyclohexene

at 140 ................................. 67

Pyrolysis of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone in Cyclohexene--

Diglyme at 820........................ 67

Photolysis of 4,5-Benzotropone Tosylhydrazone

Sodium Salt in Cyclohexene............ 68

Pyrolysis of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone in Cyclohexene. 69

Reaction of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone with Dimethyl

Fumarate at 1050...................... 69






Page..

Reaction of the Sodium Salt of B-Naphth-

aldehyde Tosylhydrazone with Dimethyl

Fumarate at 1050..................... 70

Reaction of S-Naphthaldehyde Tosylhydrazone

Sodium Salt with Dimethyl Fumarate

at 160 ............................... 71

Reaction of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone with Dimethyl

Fumarate at 1600..................... 72

General Procedure for the Photolysis of

Tosylhydrazone Sodium Salts in the

2-Butenes. ............................ 72

Photolysis of the Sodium Salt of 6-Naphth-

aldehyde Tosylhydrazone in trans-2-

Butene ..................... .......... 73

Photolysis of Benzaldehyde Tosylhydrazone

Sodium Salt in trans-2-Butene........ 74

Photolysis of the Sodium Salt of B-Naphth-

aldehyde Tosylhydrazone in cis-2-

Butene................................ 75

Pyrolysis of B-Naphthaldehyde Tosylhydrazone

Sodium Salt in cis-2-Butene.......... 76

Photolysis of 4,5-Benzotropone Tosylhydrazone

Sodium Salt in cis-2-Butene.......... 77

Photolysis of 4,5-Benzotropone Tosylhydrazone

Sodium Salt in trans-2-Butene......... 77







Pyrolysis of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone in cis-2-Butene. 77

Pyrolysis of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone in cis-2-

Butene and Benzene..................... 78

Pyrolysis of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone in cis-2-Butene

and Perfluorocyclobutane.............. 79

Pyrolysis of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone in cis-2-Butene

and Oxygen ..................... ...... SO

Pyrolysis of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone in cis-2-Butene

and trans,trans-2,4-hexadiene.......... 80

Sensitized Photolysis of the Sodium Salt of

4,5-Benzotropone Tosylhydrazone in

Benzene................................ 81

Thermal Stability of the syn- and anti-1-

(2-naphthyl)-cis-2,3-dimethylcyclo-

propanes ................ .............. 81

Stability of cis-2-Butene under Reaction

Conditions ......................... 82

2-Methyl-4,5-Benzotropone .................. 82

2-Methyl-4,5-Benzotropone Tosylhydrazone... 82

Pyrolysis of the Sodium Salt of 2-Methyl-

4,5-Benzotropone Tosylhydrazone in

Benzene................................ 83






Page

2,3-Benzotropone ............................ 84

2,3-Bentotropone Tosylhydrazone............. 84

Pyrolysis of the Sodium Salt of 2,3-Benzo-

tropone Tosylhydrazone in Benzene....... 85

LIST OF REFERENCES .................................... 87

BIOGRAPHICAL SKETCH ................................... 92











LIST OF TABLES

Table Page

1. Stereochemical Results: The Percent "Wrong
Isomer" from the Decompositions in cis-2-
Butene of the Carbene Precursors both Thermally
at 1050 and Photolytically at -25 ............. 27











LIST OF FIGURES

Lgure Page

1. Vpc trace: Pyrolysis of 26 in Cyclohexene.... 16

2. 100 MHz Nmr of 33... ............ ............. 18

3. Decoupled Nmr of 33. ........................... 19

4. Closure of vinylcarbene to cyclopropene....... 48

5. Boat Conformation of Benzocycloheptatrienyli-
dene.............. .......................... 50

6. Planar Conformation of Benzocycloheptatrienyli-
dene. ....................................... 51











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


CARBENE-CARBENE REARRANGEMENTS: A STUDY IN THE
BENZOCYCLOHEPTATRIENYLIDENE-NAPHTHYLCARBENE SYSTEM


By


Kenneth Edward Krajca

August, 1972


Chairman: W. M. Jones
Major Department: Chemistry


The rearrangement of benzocycloheptatrienylidenes to

naphthylcarbenes in solution thermally at temperatures in the

range of 1000 and photolytically at temperatures as low as

-350 is reported. The rearranged naphthylcarbenes were

detected by their reaction products with solvent. Decomposi-

tion in benzene gave the corresponding naphthylcyclohepta-

trienes in good yield, and decompositions in cyclohexane and

diglyme yielded the corresponding insertion products. In

cyclohexene, the formation of naphthylnorcaranes and naphthyl-

carbene insertion products into cyclohexene was temperature

and concentration dependent. This is consistent with a

bimolecular reaction of an intermediate with cyclohexene in

competition with a unimolecular rearrangement that gives

0-naphthylcarbene.






The rearrangement of a carbene precursor was excluded

and possible mechanisms were explored. Stereochemical studies

indicate that the singlet state of the carbene is responsible

for the rearrangement and that there is a small amount of

nonstereospecific addition which is unaffected by dilution

but is affected by the addition of triplet scavengers. This

is compatible with a singlet-triplet equilibrium wherein the

rate of triplet-singlet intersystem crossing is greater than

the rates of addition of the triplet carbene to olefin, but

the rate of triplet carbene addition to dienes (and oxygen)

must be greater than the rate of triplet-singlet intersystem

crossing. Methyl substitution has an effect upon the rearrange-

ment which may occur via a fused, twisted cyclopropene inter-

mediate (benzobicycloheptatriene) from the boat conformation

of the carbene, the planar conformation, or via a concerted

pathway.










CHAPTER I

INTRODUCTION AND BACKGROUND


Carbene-carbene rearrangement has been established as a

firm, although relatively rare, chapter in the chemistry of

divalent intermediates. In 1967, Skattebol' reported several

examples of "non-trivial" carbene-carbene rearrangements, e.g.,

that of vinylcyclopropylidene (1) to cyclopentenylidene (2).



B F> ->
Br2
1 2

In this type of rearrangement, however, the carbene carbon

retains its integrity and, since the carbene was generated by

a-elimination, a free carbene may not have been obtained. In

fact, the stereoselectivity in product formation in one case

suggested a carbenoid species.

Cais et al.2 reported a carbene-carbene rearrangement in

the deprotonation of ferrocenyltropylium fluoborate (3) with

the admonition that the carbene intermediacy was not established.





F BF4 0
3 F







Along a slightly different line, Strausz3 and coworkers

investigated the rearrangement of the carbonylcarbene derived

from the photolysis of 3-diazobutanone-2 and homologous com-

pounds in both the gas and condensed phases. Russell and

Rowland" also investigated similar systems but came to slightly

different conclusions.

In 1965, Shechter and Vander Stouw5 reported the rearrange-

ment of various methyl- and dimethylphenylcarbenes and eluci-

dated this work in a more recent report.6 In their work,

(2-methylphenyl)diazomethane (4), for example, was pyrolyzed

to yield, among other products, styrene (5), and benzocyclo-



CHN2

CH3 0,

4 5 6
butene (6). The above products and a labeling study indicated

the process was occurring via a multiple carbene-carbene

rearrangement.

Jones et al.7 later elaborated on the phenylcarbene-cyclo-

heptatrienylidene rearrangement when heptafulvalene (7) was

isolated from the gas phase pyrolysis at 2500 of the sodium

salt of benzaldehyde tosylhydrazone as well as from pyrolysis

of the sodium salt of tropone tosylhydrazone.8 Pyrolysis of



H- 'C'



7





a mixture of the sodium salts of benzaldehyde tosylhydrazone
and p-tolualdehyde tosylhydrazone resulted in the formation of
crossed dimer which proved that the rearrangement occurred in
the gas phase.
Multiple carbene-carbene rearrangements of diphenyl-
methylene (8) were also studied by Jones.9 Pyrolysis at 3500
of diphenyldiazomethane yielded fluorene (9), tetraphenyl-
ethylene (10), triphenylheptafulvene (11), diphenylheptafulva-
lene (12), and the corresponding azine. Note that these


C:


a


4-


0 0

00


13



1l


S-


2L



01
O iN


results require that the diarylcarbene expand to form the
arylcycloheptatrienylidene 13 and the arylcycloheptatrienyli-
dene contract to form a biphenylmethylene which is the
immediate precursor of the fluorene.







Wentrup and Wilczek0l also reported the reversibility of

the phenylcarbene-cycloheptatrienylidene rearrangement when

they isolated stilbene and heptafulvalene from the indepen-

dent gas phase pyrolysis at 3000 of the sodium salts of both

benzaldehyde tosylhydrazone and tropone tosylhydrazone.

Hedaya and coworkers" studied the ring contraction and

expansion of phenylcarbene in the gas phase by pyrolysis of

benzaldehyde tosylhydrazone sodium salt. They also observed

the formation of heptafulvalene as one of the reaction products

and by incorporating a labeling study on tolylcarbene'2 they

decided that very small energy barriers separate phenylcarbene,

cycloheptatrienylidene, and possible bicycloheptatriene inter-

mediates.

Lastly, M. Jones, Jr.13 investigated the interconversion

of o-, m-, and p-tolylcarbene by observing the ratios of the

styrene (5) and benzocyclobutene (6) produced in the pyrolysis

of the corresponding diazo compounds.
CHN2

CH3






CHN2
CH3

CHN2 6




CH3







It is very interesting to note that most of the

researchers on the phenylcarbene-cycloheptatrienylidene

interconversion believe that the rearrangement occurs via a
5-7 9-13
bicycloheptatriene intermediate (14). Jones and









14


Mitsuhashi" elucidated this mechanism with their study on

the importance of bond order in the gas phase carbene-carbene

rearrangement of a series of substituted naphthylcarbenes.

It was found that scrambling of the carbene occurs only

between positions having the highest bond order which augurs

well for the bicyclic intermediate as opposed to a Wolff-type

rearrangement (shown below).





C '*-





To date, the latest work in carbocyclic carbene-carbene

rearrangements was done by Jones and Gebertis on the ring

expansion of the ten w-electron 1,6-methano[10]annulenyl-2-

carbene (15). The products of the reaction are apparently







rearranged dimers and the mechanism is assumed to be similar

to that mentioned above.





^C:

15

Nitrogen analogues to the phenylcarbene-cyclohepta-

trienylidene rearrangement have been known for a long time.

The ring expansion of phenylnitrene to yield substituted

azepines was studied as early as 195816,17 and has recently

received thorough investigation.18-24 Pyrolysis16 and

photolysis24 of phenyl azide (16) in the presence of amines

led to 2-amino-3H-azepine derivatives (17) as final products.


EtNEt2




16 17


The thermal1 and photolytic21,22 deoxygenation of nitro-

benzene, as well as the thermal deoxygenation of nitroso-

benzene,18 in the presence of amines also led to 2-amino-3H-

azepines. As in the analogous carbene-carbene rearrangements,

these reactions can be envisioned as proceeding through a

bicyclic intermediate which can yield an azacycloheptatrienyli-

dene. From the experimental results, however, workers have

not been able to determine whether or not the azacyclohepta-






trienylidene is an intermediate. In fact, another mechanism,
addition of the amine to the bicyclic azirine (18), has
received much more attention.25


18
6 -0 -


Et2NH

NH
-NEt 2
0- >


S- Et NEt2






NEt2


Crow and Wentrup2 reported that the thermal generation
of 2-pyridylphenylcarbene (18a)led to carbazole (19) products
which were believed to arise via a substituted azacyclohepta-


S 0


I
19 H







trienylidene (20) intermediate or transition state. Crow and

Wentrup have extended their work on these systems27 as well

as investigated the pyridylnitrene-diazacycloheptatrienylidene

rearrangement.2e Perhaps the most interesting was the work

on 2-quinolylnitrene (21), an annelated nitrene which is








=N 2.1 2







N-"
N N:





believed to rearrange via an annelated diazacycloheptatrienyli-

dene (22).29 However, naphthyl azides have not been known to

give rise to detectable azepine.3"

The work described in this dissertation was done to

investigate the effects of annelation on the phenylcarbene-

cycloheptatrienylidene rearrangement. It was hoped that the

effects of annelation would give insight on the nucleophilicity

of the aromatic carbene, on the relative rate of rearrangement

and on the mechanism of the rearrangement. The approach was

very feasible in that the precursors for both the annelated

arylcarbene and the annelated aromatic carbenes were avail-





9


able. The systems chosen for study were 4,5-benzocyclohepta-

trienylidene (23), 2-methyl-4,5-benzocycloheptatrienylidene

(24), 2,3-benzocycloheptatrienylidene (25), and the related


S** CH3 **c a






23 24 25
naphthylcarbenes. While other benzocycloheptatrienylidenes

have been prepared and studied, they did not rearrange and

many of their reactions were typical of diarylcarbenes."3












CHAPTER II

RESULTS


The first results needed were for the model system of

phenylcarbene and cycloheptatrienylidene. Thus, the pyrolysis

of the sodium salt of benzaldehyde tosylhydrazone was effected

in diglyme at 1650 to produce what is believed to be the

phenylcarbene-diglyme insertion products. This residue, a

light yellow oil, had an nmr spectrum very similar to that of

the naphthylcarbene-diglyme insertion products videe infra);

there was also benzaldazine produced in the reaction. The

nmr spectrum of the reaction material indicated no heptaful-

valene was present, and comparative tic of the material and

a known sample of heptafulvalene was carried out using silica

gel eluting with pentane. This confirmed the absence of

heptafulvalene in the reaction material.

Tropone tosylhydrazone sodium salt was also decomposed

in diglyme at a temperature of 2100. The nmr spectrum of the

residue, a dark solid, was identical to that of heptafulvalene

with an additional small amount of aromatic resonance at 2.8 T

but none at 6.2-7.0 T (the position expected for the resonances

of any diglyme insertion products).

The aromatic carbene, 4,5-benzocycloheptatrienylidene

(23), was generated by the thermal and photolytic decomposi-







tion of the sodium salt of 4,5-benzotropone tosylhydrazone

(26) in an appropriate solvent. Pyrolysis or photolysis of

the sodium salts of tosylhydrazones form the corresponding

diazo compounds in situ.32 The diazo compounds then decompose

under aprotic reaction conditions to yield the carbenes.

The synthetic route to the sodium salt of 4,5-benzo-

tropone tosylhydrazone is shown in the scheme below. The


SCO2Et

C=O
c+ o 0

*COzEt IZ





N-N-Ts --- N-Ts
Na+ H

26


ketone, 4,5-benzotropone (27), was prepared by the method of

Thiele and Weitz33 and the tosylhydrazone by a modification

of the procedure of Closs.34 The conversion of the tosyl-

hydrazone to its sodium salt was done with sodium hydride in

tetrahydrofuran.35 The last step was carried out in a dry

box; however, contrary to some reports the sodium salts did

not appear to be hygroscopic in most cases.

In a similar manner, commercially available B-naphth-

aldehyde was converted to its tosylhydrazone36 and then to its







tosylhydrazone sodium salt. This salt was the immediate

precursor of B-naphthylcarbene.

In most cases, the naphthaldehyde tosylhydrazone sodium

salt was decomposed under the same or very similar conditions

as those of the 4,5-benzotropone tosylhydrazone sodium salt

so that the chemistry of the two carbenes could be compared

and, where possible, as a check on the authenticity of the

naphthyl products formed from the rearranged carbene.

Thus 4,5-benzotropone tosylhydrazone sodium salt was

decomposed in diglyme at 1000 to give a 29% yield of the

isomeric B-naphthylcarbene-diglyme insertion products (28).



HaCN- 0 O/ CH





280

While these isomeric compounds could not be readily separated,

there is little doubt as to their identity. The nmr spectrum

of these products shows aromatic proton absorptions at 2.00-

2.80 T and methyl and methylene protons adjacent to oxygen at

6.10-7.20 T (there are more signals than necessary in the

region of 6.60 T for methyl protons of a single product).

Other spectral properties and the elemental analysis of the

mixture are in complete agreement with the assigned structures,

and regardless of the carbene precursor videe infra), the

products formed in diglyme are the same.







The decomposition of naphthaldehyde tosylhydrazone

sodium salt in diglyme at 1000 produced a 13% yield of the

same B-naphthylcarbene-diglyme insertion products produced

in the above decomposition. The product yield from the

decomposition of the naphthaldehyde tosylhydrazone salt was

typically lower because there was competition of aldazine

formation.

Next, the photolytic decomposition of the salt of 4,5-

benzotropone tosylhydrazone in diglyme was carried out at 300

and resulted in the formation of the familiar naphthylcarbene-

diglyme insertion products.

When 4,5-benzotropone tosylhydrazone sodium salt was

heated in benzene at 800 there was formed, in 96% yield, a

product identified as 2-(2,4,6-cycloheptatrien-l-yl)naphthalene

(29). Although this compound has been prepared before, there









29

is no complete report of its physical and spectral properties.37

The existence of the cycloheptatrienyl moiety was proven by

comparison of the above compound's nmr spectrum with that of

l-phenyl-2,4,6-cycloheptatriene38 (the spectra were identical

except for the aromatic region). That it was the B-naphthyl

function (as opposed to a-naphthyl) was shown by careful







examination of the compound's ir spectrum; the absorption for

the out-of-plane bending at 861 cm-1 indicated an isolated H

on the naphthyl ring system, that at 821 cmI indicated two

adjacent H, and that at 745 cm1 was indicative of four adja-

cent H39 (the nmr of the product showed a ratio of 4:3 for

the a to 8 protons, respectively, in the aromatic region).

Photolysis at 300 of the sodium salt of 4,5-benzotropone

tosylhydrazone also produced the adduct 29 in 59% yield.

Photolysis (300) and thermolysis (1250) of the sodium

salt of S-naphthaldehyde tosylhydrazone in benzene gave, in

addition to the aldazine, 29 in 67% and 78%, respectively.

The existence of 8-naphthaldazine in the reactions

involving the B-naphthaldehyde tosylhydrazone sodium salt was

proven by comparison of the reaction product with an authentic

sample of the azine"0 which was independently synthesized."1

While decompositions of both carbene precursors in

benzene gave the same hydrocarbon products, the decompositions

of 4,5-benzotropone tosylhydrazone sodium salt in cyclohexene

were unique in that there were additional products formed

when compared to the 8-naphthaldehyde tosylhydrazone sodium

salt decompositions.

First, the pyrolysis of 8-naphthaldehyde tosylhydrazone

sodium salt was carried out in cyclohexene at 135-1450. The

relative yields of the three volatile components are as

follows: the naphthylcarbene-cyclohexene insertion product

30 (34%), the syn-norcarane 31 (26%), and the anti-norcarane







32 (40%). The aldazine was formed in 10% yield, but it is

not in the above data as they only include volatile hydro-

carbon products.













30 32 31

The insertion product 30 was readily identified by nmr;

the two vinylic and two "benzylic" protons were readily dis-

cernible. The syn- and anti-norcaranes required slightly more

attention to effect differentiation, however. The corresponding

phenylnorcarane models"' and the guidelines put forth for their

identification by Closs and coworkers3'," aided the charac-

terization of the naphthyl moieties. Thus, by analogy, the

syn-7-(2-naphthyl)norcarane 31 should have the naphthyl ring

system facing the cyclopropane ring and this conformation

would then have two separate effects on the nmr spectrum of

the compound: first, several of the cyclohexyl ring protons

would be held in the shielding cone of the naphthalene ring

system and be consequently shifted upfield as far as 0.7 ppm

compared with the anti-epimer; second, the aromatic protons

would not interact with the cyclopropyl ring and their signals

would be relatively narrower than the other compound. The

anti-epimer 32 should exist in the conformation with the







naphthyl ring system bisecting the cyclopropyl ring"4 which

would cause one of the o-protons to lie in the shielding zone

of the cyclopropane ring and to be shifted upfield approxi-

mately 0.2 ppm relative to the syn-product (of course the

cyclohexyl ring protons would be slightly downfield and not

so broadened when compared with the former).

Second, when the sodium salt of 4,5-benzotropone tosyl-

hydrazone was decomposed in cyclohexene heated to reflux (830),

five products were formed. These products were detected and

isolated by vpc. The vpc trace of the decomposition of 4,5-

benzotropone tosylhydrazone sodium salt in cyclohexene at

830 is shown in Figure 1. Two products accounted for 66% of


32
3031
30


Figure 1. Vpc trace: Pyrolysis of 26 in Cyclohexene.







the material: one is unidentified, but the other has the

properties of the spiro-adduct of benzocycloheptatrienylidene

to cyclohexene (33). The 100 MHz nmr of 33 is shown in








33

Figure 2 and the decoupled spectrum in Figure 3. Perhaps the

cyclohexyl moiety is introducing the dissymmetry present in

the spectra, but it is difficult to rationalize the large

differential chemical shift of the two different cyclohepta-

trienyl protons adjacent to the benzene ring system. The uv

spectrum, Xmax = 240 mp (log e = 4.2) and 265 mi (log e = 3.5),

compares well with that of 3,4-benzocycloheptatriene, Xmax

230 mi (log E = 4.7) and 265 my (log e = 3.7).~' The mass

spectrum of this compound indicates a molecular ion at m/e

222. The ir contributed little toward the identification
-1
except that the strong absorption at 750 cm is indicative

of an o-disubstituted benzene.'* Also, other absorption are

present in the ir spectra of both 3,4-benzocyclohepta-1,3,6-

triene'5 and the above unknown compound with approximately
-1
the same intensities (1620, 1480, 1440, 795, 745 cm and

several weak bands). The last three products and their rela-

tive yields were, respectively, (cyclophexene-3-yl)-2-naphthyl-

methane, the naphthylcarbene-cyclohexene insertion product,

(7%), syn-7-(2-naphthyl)norcarane (12%), and anti-7-(2-naphthyl)-
---- I fln /1c \




























h
























4-,








4-
0
























44,
o












oo











A
*i'


pri
~a~p-




r


3

m


--Y-


7-

zl
0


C)






a)

F-.
0
CDl
Pt


3.--- ------ ---






Pyrolysis of the sodium salt of 4,5-benzotropone tosyl-
hydrazone in cyclohexene at 1400 led to the same five products
as the lower temperature one.
The sodium salt of 4,5-benzotropone tosylhydrazone was
thermally decomposed at 820 in a 2:1 molar mixture of diglyme--
cyclohexene. Analysis of the hydrocarbon products indicated
the presence of the same five products as the other cyclohexene
decompositions with the addition of the naphthylcarbene-diglyme
insertion products. The diglyme products amounted to 27% of
the total products.
Finally, the photolysis of 4,5-benzotropone tosylhydrazone
sodium salt in cyclohexene at 300 produced the same products
as the pyrolyses plus a new unidentified one. In the
photolysis, the benzocycloheptatrienylidene addition product
33 is a major component; in the pyrolyses, the opposite is
true. In the cyclohexene--diglyme reaction, interfering
materials made accurate analysis impossible.
When cyclohexane was used for the substrate, the product
isolated in 51% yield from the decomposition of 4,5-benzo-
tropone tosylhydrazone sodium salt was (B-naphthyl)cyclohexyl-
methane (34). While the yield was not exceptional, the nmr
spectrum of the crude reaction material indicated almost
exclusively the insertion product and cyclohexane.



cc m
Z111 I'l







In an effort to trap the diazo compound of 4,5-benzo-

tropone, the tosylhydrazone sodium salt was decomposed in benzene

at 105-1080 in the presence of an equimolar amount of dimethyl

fumarate. There was considerable nitrogen evolution, and the

product isolated from the reaction was the naphthylcarbene-

benzene adduct 29 in 63% yield. The nmr spectrum of the

crude reaction material indicated only the adduct and dimethyl

fumarate. Comparative tlc, on silica gel eluted with 50:50

ethyl ether--pentane, of the known pyrazoline videe infra) and

this reaction mixture indicated no pyrazoline was present in

the latter.

Naphthyldiazomethane was treated in a similar manner.

The sodium salt of B-naphthaldehyde tosylhydrazone was decom-

posed in benzene at 105-1080 in the presence of an equimolar

amount of dimethyl fumarate. The product, an almost colorless,

very viscous oil, had all of the properties of trans-3,4-

dicarbomethoxy-5-(2-naphthyl)-2-pyrazoline (35). The oil was



MeO 2 C CO2Me



H

35

not stable to ordinary distillation conditions and even

though column chromatography on silica gel effected some

purification, it was not sufficient to provide a sample which

gave a good elemental analysis (e.g., calcd. N, 8.97; found:

N, 8.31). The ir spectrum of this compound had a strong







absorption at 3440 cm-1 indicative of N-H stretching, one at

1730 for the unconjugated ester carbonyl stretching, one at

1700 for the conjugated ester carbonyl, and one at 1555 indi-

cating a C=N bond. The nmr spectrum contained absorptions at

2.10-2.60 T indicating the naphthyl protons, a broad singlet

at 3.24 T for the proton bonded to the nitrogen, a broad

doublet (J = 9.4 Hz) for the "benzylic" proton at 4.60 -, a

double (J = 9.4 Hz) for the proton adjacent to the carbo-

methoxy group at 5.92 T, a singlet for the conjugated ester

methyl at 6.18 T, and a singlet for the unconjugated ester

methyl at 6.24 T (in addition, there were other resonances

which changed in intensity depending upon work up and purifi-

cation steps and were therefore not believed to originate

from the pyrazoline). The trans-configuration was evident

when compared with nmr data of trans-3,4-dicarbomethoxy-5-

phenyl-2-pyrazoline47 which had J = 10 Hz for the protons on

C-4 and C-5 and a chemical shift of 4.87 T for the benzylic

proton on C-5. It is also interesting to note that the above

phenyl pyrazoline was a viscous oil which resisted all attempts

to induce crystallization.' The mass spectrum had no signal

for the molecular ion, but there was one at 284 (the molecular

ion with the loss of N2). The max in ethanol were 224 my

(log E = 4.53), 275 (3.75), and 287 (3.79). Using 2-methyl-

naphthalene9 and the known 3-carbomethoxy-4-phenyl-2-pyrazo-

line50 as models, the following absorptions would be expected

in the uv: 223 my (log e = 4.22), 274.5 (3.73), and 296 (3.98).







The decomposition of B-naphthaldehyde tosylhydrazone

sodium salt in benzene at 1600 in the presence of an equimolar

amount of dimethyl fumarate gave rise to a different product

than the low temperature one. The product was identified as

trans-l,2-dicarbomethoxy-3-(2-naphthyl)cyclopropane (36) and

was isolated in 67% yield. The structure was easily desig-


O2Me



Me02C
H
36

nated trans because of the two different methyl proton absorp-

tions (either cis-cyclopropane would have had only one signal

for the two methyl groups as they would be magnetically

equivalent) and because the thermal decomposition of trans-

3,4-dicarbomethoxy-5-phenyl-2-pyrazolines is known to give

the trans-cyclopropanes .

The decomposition of the sodium salt of 4,5-benzotropone

tosylhydrazone in benzene at 1600 in the presence of dimethyl

fumarate led to the formation of 2-(2,4,6-cycloheptatrien-l-yl)-

naphthalene (29) and what is believed to be 2-(2,4,6-cyclo-

heptatrien-4-yl)naphthalene (37) in a ratio of 1.0:1.6 as

determined by nmr. The latter product could arise via a [1,51

hydrogen shift of the former; the hydrogen shift product was

not isolated but its presence was inferred from the nmr

spectrum and from work done in the phenylcycloheptatriene

series.sl

















29 37

8-naphthaldehyde tosylhydrazone sodium salt was decomposed

by photolysis in the presence of trans-2-butene to yield

1-(2-naphthyl)-trans-2,3-dimethylcyclopropane (38) along with

a small amount of cis- and unknown materials. While other


H


H3 CH



38 H

properties were consistent with this structure, the identifi-

cation of this compound was hampered by the unusual nmr

spectrum. The two signals arising from the methyl group

protons were essentially singlets (they would be expected to

be doublets). Two things were tried in order to solve this

dilemma: first, the nmr spectrum was taken in a different

solvent, benzene, which caused one of the singlets to split

by about 1.5 Hz, and,second, the corresponding phenyl cyclo-

propane was prepared and its nmr spectrum examined and found

to be very similar to the naphthylcyclopropane. Thus, the

structure is in accord with the observed spectral properties.







The photolysis of the sodium salt of B-naphthaldehyde

tosylhydrazone in cis-2-butene gave the two expected epimeric

cyclopropanes along with a small amount of trans-cyclopropane

and unknown materials. Syn-l-(2-naphthyl)-cis-2,3-dimethyl-



H3

H3 H
HH CH3

H H CH3
H

39 40

cyclopropane (39) and anti-l-(2-naphthyl)-cis-2,3-dimethyl-

cyclopropane (40) were differentiated in a manner similar to

that of the epimeric naphthylnorcaranes videe supra). In the

syn-cyclopropane 39 the methyl protons appear 0.2 ppm upfield

relative to the anti-compound, and the naphthyl resonances are

relatively less broad. Naturally, the methyl resonances were

at lower field and one of the o-protons on the naphthyl system

appeared at higher field (causing a broadening of the aromatic

resonances) in the anti relative to the syn.

Pyrolysis of the naphthaldehyde tosylhydrazone sodium

salt in cis-2-butene gave, in addition to the epimeric cyclo-

propanes, an unknown product formed in considerable amounts.

When 4,5-benzotropone tosylhydrazone sodium salt was

decomposed by photolysis in the presence of cis-2-butene, it

gave the expected epimeric cyclopropanes, a small amount of

trans-cyclopropane, and a considerable amount of unknown







material. The photolysis in trans-2-butene gave as a major

product the expected trans-cyclopropane (in addition to small

amounts of cis-cyclopropane and unknown material).

The pyrolysis of 4,5-benzotropone tosylhydrazone in cis-

2-butene yielded large amounts of the epimeric cyclopropanes,

small amounts of trans-cyclopropane, and some extraneous

materials.

The stereochemistry of the addition of the carbenes to

olefins was then determined by analysis of the amount of

trans-cyclopropane formed in the decomposition of the two

carbene precursors in research grade cis-2-butene. The

decompositions were carried out under a variety of conditions.

They were done using the neat olefin as solvent, they were

done with the olefin diluted with benzene (1:3 molar ratio,

respectively) and perfluorocyclobutane (two runs, 1:2 molar

ratio and 1:6 molar ratio, respectively), and they were done

with olefin in the presence of oxygen and trans,trans-2,4-

hexadiene (two runs, 1.0:1.5 molar ratio and 1.0:2.1 molar

ratio, respectively). Dilution had no effect upon the ratio

of cis- and trans-cyclopropanes formed; however, the presence

of oxygen and the diene significantly altered the above ratio,

producing relatively more cis-cyclopropane. When the mole

percent of trans,trans-2,4-hexadiene was greater than 66%,

there was too little cis-2-butene adduct formed to determine

the stereochemistry. The results of the stereochemical

investigation are shown in Table 1.











TABLE 1

Stereochemical Results: The Percent "Wrong Isomer"a from the
Decompositions in cis-2-Buteneb of the Carbene Precursors
both Thermally at 1050 and Photolytically at -250.

Tosylhydrazone Sodium Salt % "Wrong Isomer"c
Solvent System (molar ratio) A hv

Naphthaldehyde d
cis-2-butene 10 3

Benzotropone
cis-2-butene 7 4

Benzotropone
cis-2-butene/benzene (1:3) 6

Benzotropone
cis-2-butene/perfluorocyclobutane (1:2) 6

Benzotropone
cis-2-butene/perfluorocyclobutane (1:6) 6

Benzotropone
cis-2-butene/oxygen (saturated) 4

Benzotropone
cis-2-butene/2,4-hexadiene (1.0:1.5) 1


a 1-(2-naphthyl)-trans-2,3-dimethylcyclopropane
b research grade 99.94 mole %

c standard deviations were typically 1

ddatum only approximate due to interfering material







To be sure that the products were stable to vpc, the cis-

cyclopropane was preparatively chromatographed and then

analyzed for trans-material--none was found. Also, the olefin

was analyzed after the reaction and it was found that the olefin

had isomerized less than 1 percent during the course of the

reaction.

In hope of sensitizing the rearrangement, the sodium

salt of benzotropone tosylhydrazone was decomposed photolyt-

ically in benzene using xanthen-9-one (ET = 74 Kcal/mole) as

a sensitizer. Unfortunately, no hydrocarbon products were

isolated from the reaction.

The substituted tropone, 2-methyl-4,5-benzotropone was

made according to the method of Hielbronner52 (the conver-

sions necessary to obtain the sodium salt of the corresponding

tosylhydrazone were the same as those used for 4,5-benzotro-

pone itself).

The sodium salt of 2-methyl-4,5-benzotropone tosylhydrazone

was thermally decomposed in benzene at 1300 to yield two

products: 2-vinylnaphthalene (41) and 2-(2,4,6-cyclohepta-

trien-l-yl)-3-methylnaphthalene (42). The authenticity of the




-4Y CH3






2-vinylnaphthalene from this reaction was verified by comparison

of its spectral properties with those of commercially avail-

able material. The substituted cycloheptatrienylnaphthalene

was identified by its spectral properties and by comparison

with material obtained from the thermal decomposition of the

sodium salt of 3-methyl-2-naphthaldehyde tosylhydrazone in

benzene videe infra).

The sodium salt of 3-methyl-2-naphthaldehyde tosylhydra-
zone was thermally decomposed in benzene at 1450 and yielded

the above cycloheptatrienylnaphthalene 42 (39%) and aldazine

(42%).
The products from the decomposition of the benzo precursor

were analyzed by vpc and it was found that the relative ratios

of the products were 2-vinylnaphthalene 72%, unknown material
6%, and 2-(2,4,6-cycloheptatrien-l-yl)-3-methylnaphthalene
22%.

Another annelated tropone, 2,3-benzotropone was prepared

as shown in the scheme below53 (again the conversions to the

tosylhydrazone sodium salt were the same as those necessary

for 4,5-benzotropone).
PPA

CH2-(CH2)3-CO2H


BrZ/CCl1

SiC/DMFBr
LiCl/DMF
[ii4 ^^







The decomposition of the sodium salt of 2,3-benzotropone

tosylhydrazone in benzene at 1200 gave 1-(2,4,6-cyclohepta-

trien-l-yl)naphthalene (43). The compound was identified by









43

its spectral properties as follows: the nmr has resonances

at 2.20 T three a-protons of the naphthyl system; 2.55 r four

B-protons of the naphthyl system; 3.30 T two protons on the

4 and 5 positions of the cycloheptatriene ring; 3.70 T two

protons on the 3 and 6 positions of the cycloheptatriene

ring; 4.50 T two protons on the 2 and 7 positions of the

cycloheptatriene ring; and 6.60 T for the one proton on the

1 position of the cycloheptatriene ring. The mass spectrum

gave peaks at m/e 218 for the molecular ion, 127 for the

naphthyl ring system, and 91 for the tropylium fragment.

That it was the a-substituted naphthalene was shown by the

ratio of the a- to B-protons in the nmr spectrum and by close

examination of the ir spectrum (Cf. 2-(2,4,6-cycloheptatrien-

l-yl)naphthalene); the lack of any absorptions at 861 cm-

and 821 cm1 and the appearance of a band at 800 cm-1 (for

three adjacent H) and the mutual band at 745 cm1 was in

agreement with this structure.












CHAPTER III

DISCUSSION

To date, the interconversion of aryl and aromatic

carbenes2,6,7,9,10,12,16,18 (and nitrenes26,28) --such as the

conversion of phenylcarbene to cycloheptatrienylidene --has

been limited to the gas phase and rather high temperatures

(the exceptions to this have been the ring expansion of 1,6-

methano(10)annulenyl-2-carbene'5 and the small amount of

rearrangement observed in the photolysis at room temperature

of o-, m-, and p-methylphenylcarbeness) Also, with the

exceptions of aromatic carbene dimerizations and of the

reaction of the expanded 1,6-methano(10)annulenyl-2-carbene

with 1,2-cyclononadiene,* in no case has it been possible to

examine intermolecular reactions of any of the rearranged

carbenes. At this time, the rearrangement of 4,5-benzocyclo-

heptatrienylidene to B-naphthylcarbene and that of 2,3-benzo-

cycloheptatrienylidene to a-naphthylcarbene in solution at

temperatures as low as -350 is reported. These reactions

constitute examples of carbene-carbene rearrangements which

are apparently not subject to either of the previous restric-

tions.


W. M. Jones and P. H. Gebert, unpublished results.







For this study, the phenylcarbene-cycloheptatrienyli-

dene reaction was taken as the prototype. Phenylcarbene (44)

was generated in diglyme under conditions where the sodium

salt of tropone tosylhydrazone gives heptafulvalene and the

reaction mixture was carefully examined for cycloheptatrienyli-

dene dimer. No trace was found. Cycloheptatrienylidene

(45) was then generated under conditions where phenylcarbene

gives clean reaction with solvent and the reaction mixture

carefully analyzed for phenylcarbene insertion products. No

trace was found.

The failure of phenylcarbene to expand in solution is

probably due to a favorable competitive intermolecular

reaction with solvent. Cycloheptatrienylidene, on the other


H\C



Insertion < DivIyme g -Diglyme i Dimer


44 45

hand, is very unreactive with most solvents, preferring to

simply dimerize. Thus, its failure to contract reflects an

activation energy high enough to allow dimerization to dominate.

As one possible way to reduce the activation energy for

contraction while hopefully retaining enough of the low

reactivity of the aromatic carbene to prevent extensive

reaction with solvent, benzocycloheptatrienylidene was

studied. This system was chosen because monoannelation is







known to substantially decrease the stability of the tropylium
ion5s but it should have little effect upon the stability of
the intermediate cyclopropene. Thus, if the stability of
the carbene parallels the carbonium ion and if the rate of
contraction is reflected in the relative stability of the
intermediate, then benzocycloheptatrienylidene should contract
faster than cycloheptatrienylidene.
The carbenes were generated from the sodium salts of the
corresponding tosylhydrazones and the rearranged naphthyl-
carbenes were detected by their reaction products with solvent.
Thus, the formation of the naphthylcycloheptatriene 29 suggests
a carbene-carbene rearrangement followed by reaction of the
rearranged carbene 46 with solvent. Formation of the rearranged

H


26





10
46










29







carbene was further supported by the formation of 8-naphthyl-

cyclohexylmethane (34) upon decomposition of the salt in

cyclohexane. Considering decompositions in cyclohexene, it

is interesting to note that the relative yield of the benzo-

cycloheptatrienylidene adduct (33) appears to decrease with

increasing temperature.

The presence of 33 and its apparent decrease with

increased temperature is consistent with a bimolecular

reaction of the unrearranged carbene with cyclohexene (to

give 33) in competition with a unimolecular rearrangement

that gives 8-naphthylcarbene. Lastly, formation of the

various insertion products can be taken as strong evidence5s

for formation of the rearranged carbene.

The mechanism of the carbene-carbene rearrangement, how-

ever, is quite a detailed problem. Initially, one must con-

sider the rearrangement of a carbene precursor. Thus, the

decompositions of B-naphthaldehyde tosylhydrazone sodium salt

and an equivalent amount of 4,5-benzotropone tosylhydrazone

sodium salt were carried out under identical conditions in

the presence of an equimolar amount of dimethyl fumarate.

As expected, the $-naphthyldiazomethane reaction gave as the

primary product the pyrazoline. In contrast, the benzotropone

tosylhydrazone salt reaction gave the now familiar benzene

addition product of 8-naphthylcarbene 29 with no detectable

trace of the pyrazoline 35. When the reactions were carried

out at higher temperatures, the former yielded the 1,2-

dicarbomethoxy-3-naphthylcyclopropane 36 and the latter gave,







in addition to the usual f-naphthylcarbene-benzene adduct, a

new product 37. The nmr of the unisolated material suggests

that it is the thermal (1,5) hydrogen shift product of the

original adduct. All of the above data are consistent with

the rearrangement occurring via a carbene, not a carbene

precursor.

Once it was determined that a carbene was probably the

rearranging species, it became necessary to differentiate

between rearrangement occurring from the singlet state and

that from the triplet state and knowledge of the multiplicity

of the initial carbene was imperative. In principle, this

facet of the problem may be explored by investigating the

stereochemistry of the addition of rearranged 8-naphthyl-

carbene to olefins. Stereospecific addition is taken as

strong evidence for the reaction of the singlet state, whereas

the triplet state appears to add nonstereospecifically.75,s8

Furthermore, the ground state of B-naphthylcarbene has been

shown to be triplet.59 Thus, a high degree of stereospecific

addition would point to the singlet as the reacting species

(unless the singlet and triplet are in equilibrium --this

will be discussed below).

The rearrangement via the triplet state might occur as

shown in the scheme below (this is simply a diradical form

of the cyclopropene mechanism, vide infra).



















Photolytically, in the pure olefin, B-naphthylcarbene

from both precursors gave 96-97% stereospecificity which is

in good agreement with the work of Closs"3 who found 95-97%

stereospecificity with phenylcarbene in pure olefins.

Thermally, the stereospecificity was less than the cor-

responding photochemical reactions (ca. 93%); this may be

because of a thermal dependence of intersystem crossing.57

It is in agreement with the amount of nonstereospecificity

observed in the addition of thermally generated dicyano-

carbene to cis-2-butene (8% in neat olefin), however, singlet-

to-triplet transition in dicyanocarbene is competitive with

addition, and thus the stereospecificity is sensitive to

dilution effects.60

The dilution effect is caused by the different concen-

tration dependence of intersystem crossing and addition to

the olefin; the former is unimolecular and the latter, of

course, is dependent upon olefin concentration." When

applied to the naphthylcarbene system, dilution either with

benzene or octafluorocyclobutane had no effect upon the

stereospecificity.







Another experimental test for multiplicity is scavenging

of paramagnetic species by oxygen or dienes. As Closs

states,57 the stereospecificity should be increased in the

presence of a diene (if the triplet is not in rapid equili-

brium with the singlet) because the scavenging of the para-

magnetic species "results in a correspondingly greater pro-

portion of the singlet-state reaction." Thus, when the B-

naphthylcarbene is generated from the salt of 4,5-benzotropone

tosylhydrazone in the presence of olefin and oxygen, the

addition is somewhat more stereospecific. By making some

approximations from existing data,61 namely that the solubility

of oxygen in benzene is similar to that of butene and that the

solubility is a linear function of temperature, a saturated

solution of 120 millimoles of butene should contain ca. 0.2

millimoles of oxygen under reaction conditions. This concen-

tration was apparently sufficient to increase the stereo-

specificity by 2% (which was also the amount it was increased

when applied to the fluorenylidene system by M. Jones, Jr.).62

Furthermore, more effective scavenging was accomplished

by utilizing trans,trans-2,4-hexadiene. In this case the

effect was pronounced in that the stereospecificity was

increased to 99%. In the hexadiene experiments, a large

part (ca. 90%) of volatile product was apparently from

reaction with the diene (relative to the amount of reaction

with butene as determined by vpc). This is quite in line

with the data of Moss'5 who, using similar conditions,

reported that approximately 70% of the reaction product







appeared to be derived from the reaction of phenylcarbene

with the diene.

In summary, the (-naphthylcarbene added to olefins with

a high degree of stereospecificity which was unchanged by

dilution but was increased by the addition of triplet

scavengers. These data are comparable with a scheme in which

there is a thermally driven singlet-triplet equilibrium

wherein the stereospecificity is independent or only slightly

dependent upon olefin concentration. If there is a rapid

singlet-triplet equilibrium, one can no longer be assured

that the singlet is the rearranging species. The rearrange-

ment could be occurring via the triplet state, but since

there is an equilibrium it might not be reflected in the

stereochemistry.

These data appear inconsistent with a scheme in which

intersystem crossing is in effective competition with addition

of the singlet to olefins as in the case of fluorenylidene.62

The stereospecificity of addition of fluorenylidene to olefins

is dependent upon both the concentration of olefin and the

addition of triplet scavengers. They are also incompatible

with a scheme where there is a rapid singlet-triplet equili-

brium in which the stereospecificity is unaffected by the

addition of triplet scavengers (as in the case of diphenyl-

carbene).57

Initially it seems that a dicotomy exists, but one can

envision a system whereby all of the above facts can be

readily explained and which leaves little doubt but that the

initially formed B-naohthvlcarbene is a sinplet.







The following scheme indicates the effects of changing

the concentrations of diene and olefin upon cis- and trans-

cyclopropane ratio; the explanation of symbols is as follows:

B = benzocycloheptatrienylidene

S = singlet naphthylcarbene

T = triplet naphthylcarbene

D = diene (2,4-hexadiene)

0 = cis-2-butene

P = diene-carbene products


B k--- S




ki [01






cis-


d is= k [0] [S] + k7[O] [T]


ks [D] > p


k7 (0]


k, [O]


trans-


d trans
dt = k4l [O] (T]


d cis
i -t ki[0] [S] + k,[0] [T]
d trans k4 [0] [T]



Integrate over all time and assume the right-hand side to be

constant.







cis k [O] [S] + k7 [0] [T] ki [S] k7
trans k4 [0] [T] I TIV T (1)

Assume a steady-state concentration for [T] which is "particu-

larly good when the intermediates are very reactive and,

therefore, present at very small concentrations.""6

d[T]
= k [S] k [T] kk[T [- ] [T] k [0] [T) k5 [D] [T] = 0


Sk2[S]
[T] = k + k[0O] + k7 [0 + ksl[D (2)


Substitute for [T] from eq. (2) into eq. (1) and simplify

cis k1k3 + kIk4 [O] + kik7 [O] + klks[D] + k2k7
trans k2k4

If there is a rapid equilibrium, k3 >> k [O], k[O]0, ks[D]

and k2 >> ki[0].

Then cis klk3
trans R214i (3)

and, the ratio is independent of olefin and diene concentra-

tions.


If the reaction is irreversible, k [0] >> k3, k [0] >> k3.

Disregard the diene for first case.

Then cis ki(k + k7) [0] + k2k7
trans k2Ik

and the ratio is dependent upon olefin concentration.


Now include the diene in the scheme k [0] >> k3, k7 [0]>> ks,

and ks [0] >> k.

cis kiks[D] + ki(k4 + ky) [0] + k2k7
trans k2k4 (4)

and the ratio is dependent upon diene and olefin concentra-







If, however, k3 >> k4 [0], k3 >> k7 [0], but ks [D] >> k3 then

cis kiks [D] + k2k7 (
trans k2k--- (

and the ratio is dependent only upon the diene concentration.

One must consider, however, that the rearrangement might

be going via the triplet benzocycloheptatrienylidene (one

need not concern oneself with triplet benzocycloheptatrienyli-

dene rearranging to singlet naphthylcarbene). Thus, the

scheme below indicates entry into the triplet rearranged

carbene.
B

k D
p, keD] S k kD [D] p
k3


ki[0] k [0]

k7[0]

cis trans


d is = k [0] [S] + k7 [0] d[T k4 [0] [T]


Integrate as in the first case

cis k [O] [S] + k7 [0] [T ki[S] k (6)
trans k [0] [T] kTTT E (6)

Assume a steady-state concentration of [S].

d ] = k [T] k [S] k [O] [S]- ka[D] [S] = 0


k3 [T]
[S] = k, + k [O] + k [D]







Substitute [S] from eq. (7) into eq. (6) and simplify.


cis klk3 k7
trans k k2 + kO + ka [D] ) (8)

If ka[D] >> k2, but k2 >> ki[0] then


cis = klk3 k7
trans +kk [D] T (9)

and the ratio is inversely proportional to the diene concen-

tration.

Finally, one might envision a scheme wherein the benzo-

cycloheptatrienylidene is the intermediate which undergoes

the singlet-triplet intersystem crossing. Each state of the

unrearranged carbene then yields the corresponding B-naphthyl-

carbene as shown in the scheme below; the explanation of

symbols is as follows:

Bs = singlet benzocycloheptatrienylidene

Bt = triplet benzocycloheptatrienylidene

Ns = singlet naphthylcarbene

Nt = triplet naphthylcarbene

D = diene

O = cis-2-butene

P = diene-carbene products


Bs Bt D p



Ns Nt



cis- trans-







There would be no dilution effect because intersystem

crossing and rearrangement are both unimolecular; the

scavenging effect would arise from reaction of diene with

the unrearranged carbene. In agreement with the arguments

above, the singlet still must be the state by which most of

the rearrangement occurs in order to explain the high degree

of stereospecificity observed.

Excluding the benzocycloheptatrienylidene intersystem

crossing, what is required for the explanation of the facts

concerning the stereospecificity of B-naphthylcarbene addi-

tion is that the rate of triplet-singlet intersystem crossing

proceeds at a rate considerably greater than those of the

additions of the triplet carbene to the mono-olefin. Also,

the rate of triplet addition to the diene (and oxygen) must

be greater than the rate of triplet-singlet intersystem

crossing. Accordingly, it has been reported that diphenyl-

carbene reacts with 1,3-butadiene more than one hundred times

faster than unconjugated olefins.6 The above kinetic scheme

depicts the desired situation in eq. (5) and is also compatible

with the earlier situations of fluorenylidene as shown in

eq. (4) and diphenylcarbene as shown in eq. (3). It also

vitiates the mechanism whereby the triplet is the rearranging

species because the addition of diene would be required to

decrease the cis-trans ratio as shown in eq. (9).

With the triplet pathway ruled out, at least four

mechanisms have been considered which arise from the singlet

state of the unrearranged carbene. The singlet mechanisms







are a carbocyclic version of the Wolff rearrangement, a

Skattebol-type rearrangement, that going via a fused cyclo-

propene intermediate, and a concerted rearrangement.

The Wolff-type rearrangement (or perhaps more accurately

the "retro-Wolff" rearrangement) is shown below. This

..7H
C
.. + H








mechanism is not very favorable for two reasons. First,

annelation should retard it because of loss of aromaticity

in the benzene ring. Second, Jones and Mitsuhashi have postu-

lated that the Wolff and the cyclopropene mechanisms would

differ experimentally in that the latter mechanism should be

favored by high double bond character whereas the Wolff

mechanism should be retarded." Their work on the importance

of bond order in the interconversion of aryl and aromatic

carbenes by studying the gas-phase, carbene-carbene rearrange-

ment of a series of substituted naphthylcarbenes,showed that

net cleavage of bonds of high bond order is observed; net

cleavage of bonds of low bond order is not. Thus, the

evidence mitigates against a Wolff mechanism.

Another mechanism which can be written for the contrac-

tion of cycloheptatrienylidene (and also for benzocyclohepta-

trienylidene) is essentially the Skattebol' vinylcyclopropyli-






dene-cyclopentenylidene rearrangement with cleavage of
different bonds. However, the effect of annelation argues
against this possibility since it should retard norcaradiene
formation (to prevent loss of aromaticity) and hence the rate
of contraction.
H

> /
.C






The differentiation of the mechanisms involving the fused
cyclopropene (route a) and the concerted pathway (route b)
present a subtle problem. In fact, unless the benzobicyclo-
heptatriene intermediate can be trapped or observed (spectro-
scopically, etc.) there can be no real distinction between
the two. If the reaction is not concerted, the activation



H\ H\
c:


/-b9-9>-
8 89







energy for ring opening must be quite low* as evidenced by

the fact that benzobicycloheptatrienylidene contracts to

B-naphthylcarbene at temperatures as low as room temperature.

The low activation energy is not unreasonable since the

energy lost in cleaving the single bond of the twisted cyclo-

propene (the benzobicycloheptatrienylidene) might well be of

the same order of magnitude as the naphthyl resonance energy

gained. In the model system it has been suggested that

"relatively small energy barriers separate phenylcarbene,

cycloheptatrienylidene, and bicycloheptatrienylidene isomers."12

For the discussion of a detailed mechanism of the

rearrangement it will be assumed that the process occurs via

the fused cyclopropene intermediate since this facilitates

the dissection of the problem and because it seems intuitively

likely that the cyclopropene is a distinct intermediate.

Accordingly, Bergman6 recently reported that the thermal

isomerization of a substituted cyclopropene very likely went

through a vinylcarbene intermediate. He gave no suggestions

as to the pathway of ring opening and closure except to rule

out a "diradical" mechanism.


Assuming that the intermediate has a half-life of 0.1 sec

and that the pre-exponential factor (A) is similar to that for

cyclopropene opening,6s a value of ca. 15 Kcal/mole is found

for the energy of activation at 270.







Thus while the preferred conformation for closure of

vinylcarbenes to cyclopropenes is unknown, it may occur

from a structure in which the filled orbital of the carbene

is orthogonal to the a-system which was suggested by Closs67

and by calculations which imply that this should be the

conformation of the ground-state singlet of vinylcarbene.68

Using Zimmerman's69 MO Following approach to correlation

diagrams, one can arrive at the preferred conformation of the

rearranging (or rearranged) carbene. This approach is applied

to cases where there is no element of symmetry and which con-

sist of a linear array of orbitals. Considering benzocyclo-

heptatrienylidene and treating the system as a vinylcarbene-

cyclopropene addition, the remainder of the benzenoid system

is disregarded (the subsequent ring opening is just the

reverse of the addition). Application of Zimmerman's "four

basic rules" yields the correlation diagram shown in Figure 4.

It is immediately obvious that p, P4 is the occupied orbital

(in the singlet state) and, since it accepts the electron

pair, it will have added s character. The final result is

that of the benzocycloheptatrienylidene with the vacant

orbital vertically oriented (pl + P4) and conjugated with

the w-system, and the orbital containing the non-bonded

electrons, s + (pl P4) weighted, horizontally oriented in

a plane containing the sigma framework.












1 4



2 _


(/23) 12
01 2


(1,3)

S," ( 3 )

+1-2+3-4


S (2.,3) *
3 4


(2)

pi+ps .1.. +-+1-2-3+4


PI-P, --
(1)
+1+2-3-4\


(o)
T (0 +1+2+3+4
S23


(0.1 4


12Figure 4. Closure of Vinylcarbene to Cyclopopene.

Figure 4. Closure of Vinylcarbene to Cyclopropene.








In hope of elucidating the mechanism somewhat, the

effect of methyl substitution upon the rate of carbene-

carbene rearrangement was cursorily examined. From the

preferred formation of 41 versus that of 42 in the decompo-

sition of the sodium salt of 2-methyl-4,5-benzotropone tosyl-

hydrazone in benzene, it appears that alkyl substitution

favors rearrangement. The validity of this conclusion


H CH3
C CHa CH3






48 47






CH3

42 41
rests on the fact that neither 3-methyl-2-naphthylcarbene (48)

nor methyl-2-naphthylcarbene (47) ring expands under the

reaction conditions and thus indicates that both reactions

are irreversible.* It is recognized that this datum will

not enable one to pinpoint a single mechanism, but in order


* From the product distribution, the free energy differ-

ence between the two product transition states is on the

order of 1 Kcal/mole at 1300.








to explain it, attention must be focused on some interesting

concepts about this general type of rearrangement. In dis-

secting this problem, two types of interactions or conforma-

tions must be considered: a boat-shaped system wherein the

ring containing the carbene center is puckered and delocali-

zation of n-electrons into the carbene p orbital is minimal,

and a planar system with delocalization of r-electrons into

the vacant p orbital of the carbene (similar to cyclohepta-

trienylidene8 which calculations imply has a planar struc-

ture).* In each of these two conformations, one must examine

three effects: steric, geometric, and electronic.

Models suggest that steric effects are unimportant

since in neither conformation is the methyl group able to

significantly aid in the formation of the transition state by

lessening any non-bonded interactions.

The transformation from the boat conformation (Figure 5)

could be envisioned as occurring by interaction of the empty











CH3
Figure 5. Boat Conformation of Benzocycloheptatrienylidene.


J. Sabin, Physics Department, University of Florida,

personal communication.







p orbital of the carbene with the rotating p orbital of the

y-carbon to form the new sigma bond and by interaction of

the sp2 orbital of the carbene with the p orbital of the

B-carbon to yield the twisted cyclopropene double bond.

From an examination of models, it appears that in the

boat conformation there is very good orbital orientation for

efficient overlap. Thus, it seems readily adapted to the

formation of a fused, twisted cyclopropene (i.e., the ground

state geometry of the boat form closely resembles that of a

possible transition state). It is quite possible that the

boat form is the lower energy conformation in this system in

spite of the assumption that the benzotropylium cation has a

planar structure.70 However, coplanarity is not requisite

as the activation energy for the rearrangement may include

the energy necessary for the planar system to become puckered.

In the planar case (Figure 6), the cyclopropene sigma

bond would be formed by the interaction of the back lobe of

the inverting sp2 orbital on the carbene carbon with the

rotating p orbital on the y-carbon. Localization of a pair


Figure 6. Planar Conformation of Benzocycloheptatrienylidene.








of n-electrons in the still conjugated p orbitals of the a-

and B-carbons would then form the new double bond (in a

manner similar to the nucleophilic attack of carbenes upon

electron-deficient double bonds).8

The planar form has to rehybridize to accomplish the

inversion at the carbene center (this is not required of

vinylcarbene cyclization). From examination of models, this

rehybridization introduces strain into the ring before there

is what appears to be good orbital overlap; this could increase

the energy of activation for closure. That is, in contrast

to the boat form, in this case there seems to be less initial

interaction leading to the rehybridization in that initially

the two potentially interacting orbitals are orthogonal.

The published electron effects are obscure and, conse-

quently, lend very little aid to differentiation of the two

modes of attack. Closs attributes alkyl substitution effects

to the possibility of both steric and electronic components

in the formation of cyclopropenes from the ring closure.of

vinylcarbenes;67 it appeared, though, that the steric portion

was dominant. Closs also observed that an alkyl group in the

olefinic position of the cyclopropene was considerably less

effective in its ability to stabilize the cyclopropene than

alkyl groups at the saturated center.71

From an examination of possible electronic effects in

the boat conformation, it appears that in the formation of

the transition state of the rearrangement the B-carbon

acquires a partial positive charge. This charge deficiency







could arise from loss of conjugation with the p orbital of

the y-carbon due to the latter's rotation toward the carbene

center. What the electron deficiency requires is a greater

degree of bond breaking between B- and y-carbons than bond

formation between the a- and B-carbons (shown below) which













CH3



is not unlike the unequal bond formation predicted for the

electrophilic addition of carbenes to double bonds.72 It is

known that alkyl substitution facilitates this type of addi-

tion. 3

Unfortunately, one cannot make conclusive predictions

about the electronic effects of the methyl group in the

planar conformation. There is the possibility, though, that

the methyl group would have little or no effect upon the rate

of the rearrangement. Thus, concerning the closure of vinyl-

carbenes to cyclopropenes, Closs67 stated that with progres-

sive rotation of the y-carbon there was the possibility of a

decrease of r-electron density at that site due to the forma-

tion of the double bond between the a- and B-carbons








(implying little change in electron density at the B-carbon).

Using the same reasoning, it would appear that there would

be little or no charge deficiency on the methyl-substituted

3-carbon of the planar system resulting in little or no

effect by the methyl group on the rearrangement.

It should now be pointed out that while geometric and

electronic effects do not form any real basis for prediction

of a preferred pathway, they are certainly consistent with

the "electrophilic-like" type of interaction discussed

earlier. Thus, the prediction of Closs and the calculations

of Zimmerman need not be incorrect as vinylcarbene may

rearrange in the manner described by them. But, carbocyclic,

aromatic carbenes may well rearrange by the other pathway

due to electronic effects brought about by geometric constraints.

For example, the apparent similarity of the boat form to a

possible transition state, and, in contrast to the assumed

geometry for the closure of vinylcarbenes,67 the geometry of

cycloheptatrienylidenes is such that the sp2 orbital of the

carbene is trans- to the double bond.

A clue to the reason for the rather dramatic effect of

annelation on the ease of ring contraction may be found in

the effect of annelation on the pKR+ values of model cations.5

Carbonium ions should be fair models for these carbenes since,

in aromatic carbenes, the vacant orbital is probably conju-

gated with the 7-system with the non-bonded pair of electrons

in the plane of the sigma framework.7 The tropyl cation has

a value of 4.7 and the benzotropyl cation has a value of 1.7.







Annelation would not be expected to substantially change

the stability of the intermediate, but annelation of the

tropyl cation causes a marked decrease in the pKR+ signaling

a substantial destabilization. Thus, the energy of activa-

tion for ring contraction should be less in the annelated

system than in the nonannelated one.

von R. Schleyer* has done "back of the envelope" calcu-

lations on the "strain energy" on phenylcarbene, cyclohepta-

trienylidene, and the bicycloheptatriene and come to the

conclusion that they are all of similar energy. Thus, it

appears reasonable that even modest annelation effects could

be enough to cause the energetic of the annelated system to

favor ring contraction over the ring expansion exhibited in

the cycloheptatrienylidene series.

Lastly, in order to test the generality of the benzo-

cycloheptatrienylidene-naphthylcarbene rearrangement, the

sodium salt of 2,3-benzotropone tosylhydrazone was decomposed

in benzene to yield the a-naphthylcycloheptatriene. The

smooth rearrangement fits perfectly into the overall picture

of the rearrangement.

In summary, benzocycloheptatrienylidenes rearrange to

naphthylcarbenes in solution thermally at temperatures in

the range of 1000 and photolytically at temperatures as low

as -350 with the rearranged carbenes being detected by their

reaction products with solvent. The rearrangement may occur


P. von R. Schleyer, Princeton University, personal com-

munication.





56

via a fused cyclopropene intermediate from the boat form of

the singlet unrearranged carbene, from the planar form of

the singlet, or via a concerted pathway.












CHAPTER IV

EXPERIMENTAL

General.--Melting points were taken in a Thomas-Hoover

Unimelt apparatus and are uncorrected. Elemental analyses

were performed by Atlantic Microlab, Inc., Atlanta, Georgia.

Ultraviolet spectra (uv) were recorded on a Cary 15 double-

beam spectrophotometer using 1 cm silica cells. Infrared

spectra (ir) were recorded with a Beckman IR10 with absorp-

tions reported in reciprocal centimeters. In all cases where

the KBr pellet technique was not used, sodium chloride plates

were substituted. Nuclear magnetic resonance spectra (nmr)

were determined on a Varian A-60A high resolution spectrometer

or a Varian XL 100 spectrometer. Chemical shifts are reported

in tau (T) values from internal tetramethylsilane standard.

Mass spectra were determined on a Hitachi model RMU-6E mass

spectrometer.

Analytical thin-layer chromatography (tlc) was accom-

plished on 2 in x 8 in plates coated in these laboratories

with 0.25 mm layers of E. Merck HF-254 silica gel. Components

were visualized by their quenching of fluorescence under uv

light. Vapor phase chromatography (vpc) was carried out

using a Varian Aerograph 90-P thermal conductivity instrument

using column A (18 ft x 0.25 in in 20% SE-30 on Chromosorb W

at 2100) or column B (3 ft x 0.25 in 15% SE-30 on Chromosorb

W at 1900) and a Varian Aerograph Series 1200 flame ioniza-







tion instrument using column C (9 ft x 0.125 in 5% SE-30 on

Chromosorb W at 1550). The analytical technique for deter-

mining product ratios from vpc data was that of cutting and

weighing. All chemicals were reagent grade unless otherwise

stated. Diglyme (diethylene glycol dimethyl ether) and

tetrahydrofuran were dried by passage over activity grade I

Woelm alumina and subsequent storage over CaH2. The analyzed

research grade cis-2-butene was from Matheson Gas Products,

Inc. (cis-2-butene, 99.94%; trans-2-butene, 0.04%; and buta-

diene, 0.02%).


Pyrolysis of the Sodium Salt of Benzaldehyde Tosylhydra-

zone in Diglyme.--To 30 ml of dry diglyme in a 3 oz Fischer-

Porter Aerosol Compatibility Tube was added 0.10 g (0.34

mmol) of the sodium salt of benzaldehyde tosylhydrazone.38

The sealed tube was placed in an oil bath preheated to 1650

for 30 min. At the end of this time all trace of color of

the diazo was gone, leaving the solution colorless. The

mixture was allowed to cool, poured into water (200 ml), and

extracted with pentane (three 30 ml portions). The combined

pentane extracts were washed with water (three 50 ml portions),

dried (MgSO4), and concentrated on a rotary evaporator under

reduced pressure. The nmr spectrum of the residue, a light

yellow oil, indicated no heptafulvalene was present, only

what is believed to be the phenylcarbene-diglyme adducts.

The nmr (CDCls) showed r 2.80 (phenyl protons) and 6.5

(diglyme protons). In addition, there was aldazine produced

in the reaction. Comparative tic of the residue with a






known sample of heptafulvalene was carried out using silica

gel eluting with pentane. This confirmed the absence of

heptafulvalene in the reaction products.


Pyrolysis of the Sodium Salt of Tropone Tosylhydrazone

in Diglyme.--Into a Carius tube was placed 80 mg (0.27 mmol)

of the sodium salt of tropone tosylhydrazone8 and 10 ml of

dry diglyme. The sealed tube was immersed in an oil bath

preheated to 2100 and allowed to remain for 30 min. Upon

cooling, the tube was opened and the contents poured into

water (120 ml) and extracted with pentane (three 33 ml por-

tions). The combined pentane extracts were washed with

water (three 50 ml portions) and dried (MgSO). The dry

pentane solution was concentrated on a rotary evaporator

under reduced pressure to yield a very dark solid. The nmr

spectrum of the residue was identical to that of heptaful-

valene with a small amount of aromatic resonance at 7.2 T,

but none at 6.2-7.0 .(the position expected for any diglyme

insertion products).


4,5-Benzotropone.--The 4,5-benzotropone used in this

research was prepared by the method of Thiele and Weitz3

with the exception that a steel high pressure reactor was

used in place of a sealed glass tube.


4,5-Benzotropone Tosylhydrazone.--In a typical run,

2.00 g (0.013 mol) of 4,5-benzotropone, 2.38 g (0.013 mol)

of p-toluenesulfonylhydrazide, and 2 drops of cone sulfuric

acid were placed in 55 ml of 95% ethyl alcohol and heated at







reflux for 1 hr. Upon cooling, 4,5-benzotropone tosylhydra-

zone precipitated from the solution and was isolated by fil-

tration. Recrystallization from absolute ethyl alcohol

yielded 2.5 g (51%) of the product. There were two crystal

forms of the tosylhydrazone: red plates (mp 186-1890) and

yellow needles (mp 180-1850). The other properties of the

tosylhydrazone were as follows: ir (KBr) 3200, 1638, 1325,

1165, 575, 555 cm-l; nmr (acetone-d6) T 2.00-2.80 (A2B2, 4H,

J=8, toluyl aromatic), 2.62 (s, 4H, benzo), 2.90-3.80 (m, 4H,

cycloheptatrienyl), 7.60 (s, 3H, toluyl methyl); mass spectrum

324 (M+).

Anal. Calcd. for C18Hi6N202S: C, 66.64; H, 4.97; N,

8.64; S, 9.89. Found: C, 66.52; H, 5.07; N, 8.57; S, 9.97.


B-Naphthaldehyde Tosylhydrazone.--In a typical run,

B-naphthaldehyde (Aldrich Chemical Co.), an equivalent amount

of p-toluenesulfonylhydrazide, and a few drops of conc HC1

were placed in 95% ethyl alcohol and allowed to stir overnight

at room temperature and the resulting crystals filtered and

recrystallized from ethyl alcohol to give the tosylhydrazone.

The product had a mp 1750, lit.36 1740.

General Preparation of the Sodium Salts of Tosylhydra-

zones.--The sodium salts were prepared by dissolving the

tosylhydrazone in dry THF and adding one equivalent of sodium

hydride (57% in mineral oil Alfa Inorganics) slowly with

stirring. The mixture was allowed to stir for 1 hr. At the

end of this period, pentane was added to precipitate the







sodium salt (this was not always necessary). The salt was

filtered, washed with additional pentane, and dried. The

entire operation was carried out in a dry box, although some

of the salts seemed to be stable to laboratory conditions.


Pyrolysis of the Sodium Salt of 4,5-Benzotropone Tosyl-

hydrazone in Diglyme.--To 13 ml of dry diglyme in a 3 oz

Fischer-Porter Aerosol Compatibility Tube was added 0.45 g

(1.3 mmol) of the sodium salt of 4,5-benzotropone tosylhydra-

zone. The sealed tube was placed for 20 min in an oil bath

which had been preheated to 1000. At the end of this time

78% of the theoretical amount of nitrogen had been evolved.

The reaction mixture was allowed to cool, poured into water

(200 ml), and extracted with pentane (three 30 ml portions).

The combined pentane extracts were washed with water (three

50 ml portions), dried (MgSO4), and concentrated on a rotary

evaporator under reduced pressure. The remaining yellow oil

was chromatographed on alumina and eluted with ethyl ether to

yield 103 mg (29%) of the naphthylcarbene-diglyme insertion

products. Although the yield was only 29%, the nmr spectrum

of the crude reaction mixture showed mainly diglyme and the

adducts. The adducts had the following properties: ir (film)

3050, 2920, 2880, 1600, 1450, 1100, 860, 820, and 750 cm-1;

nmr (CDCls) T 2.00-2.80 (m, 7H, naphthyl), 6.10-7.20 (m, 15H,

diglyme and benzylic); mass spectrum 274 (M+).

Anal. Calcd. for C17H220s : C, 74.42; H, 8.08; 0, 17.49.

Found: C, 74.59; H, 8.05; 0, 17.36.







The sodium salt of B-naphthaldehyde tosylhydrazone was

thermally decomposed and worked up in a manner analogous to

the above pyrolysis. The naphthylcarbene-diglyme adduct was

isolated in 13% yield; the major product was naphthaldazine.

The adduct's nmr spectrum was identical to that of the

products from the pyrolysis of the sodium salt of 4,5-benzo-

tropone tosylhydrazone videe supra).


Photolysis of the Sodium Salt of 4,5-Benzotropone Tosyl-

hydrazone in Diglyme.--To 15 ml of dry diglyme in a photolysis

vessel which consisted of a Pyrex tube with a side arm and

equipped with a small mechanical stirrer, was added 250 mg

(0.72 mmol) of the sodium salt of 4,5-benzotropone tosylhydra-

zone. The mixture was rapidly stirred and the photolysis

carried out by mounting the apparatus vertically alongside

and as close as possible to a 550 watt Hanovia medium pressure

mercury lamp in a Pyrex tube. Both the vessel and the tube

containing the lamp were immersed in a circulating water

bath which kept the temperature at 300. The salt was photolyzed

for 2 hr with 100% of the theoretical amount of nitrogen

being evolved as monitored by a gas buret fitted to the side

arm of the photolysis vessel. The reaction mixture was

worked up as in the above pyrolysis to yield 51 mg (25%) of

the naphthylcarbene-diglyme insertion products. It should

be noted that while the yield was low, the nmr spectrum of

the crude reaction mixture indicated that the diglyme adducts

were the major products.







Pyrolysis of the Sodium Salt of 4,5-Benzotropone Tosyl-

hydrazone in Benzene.--To a 3 oz Fischer-Porter Aerosol

Compatibility Tube containing 35 ml of benzene was added

0.20 g (0.58 mmol) of the sodium salt of 4,5-benzotropone

tosylhydrazone. The sealed tube was placed in an oil bath

preheated to 1200 and allowed to remain for 2.5 hr. The

color of the reaction mixture changed from orange to light

yellow during the course of the reaction. Upon cooling, the

nitrogen evolution was monitored and 81% of the theoretical

amount had evolved. The reaction mixture was filtered and

the residue was washed with ethyl ether. The total filtrate

was concentrated on a rotary evaporator under reduced pressure

to give 122 mg (96%) of crude 2-(2,4,6-cycloheptatrien-l-yl)-

naphthalene. Recrystallization from abs methyl alcohol

yielded 68 mg (54%) of yellow crystals mp 85-860 (sublimation

at 900 and 0.1 mm Hg gave white plates with same mp): ir

(KBr) 3060, 3020, 1600, 1500, 1280, 1260, 950, 900, 860, 820,

745, 700, 480 cm-1; nmr (CDC13) T 2.10-2.70 (m, 7H, naphthyl),

3.26 (broad t, 2H, 4 and 5 cycloheptatrienyl), 3.55-3.90

(complex m, 2H, 3 and 6 cycloheptatrienyl), 4.33-4.70 (m, 2H,

2 and 7 cycloheptatrienyl), 7.10 (m, 1H, methine); mass

spectrum 218 (M+).

Anal. Calcd. for C17H14: C, 93.54; H, 6.46. Found:

C, 93.39; H, 6.48.

The sodium salt of F-naphthaldehyde tosylhydrazone was

pyrolyzed and worked up in a manner analogous to the one

above to yield 78% 2-(2,4,6-cycloheptatrien-l-yl)naphthalene

and 6% of the aldazine.







Photolysis of the Sodium Salt of 4,5-Benzotropone Tosyl-

hydrazone in Benzene.--To the photolysis vessel, previously

described in the photolysis of 4,5-benzotropone tosylhydrazone

sodium salt in diglyme, containing 60 ml of benzene was added

0.10 g (0.29 mmol) of the sodium salt of 4,5-benzotropone

tosylhydrazone. The mixture was stirred and irradiated with

a 550 watt Hanovia medium pressure mercury lamp for 30 min

at 300. The nitrogen evolved was 84% of the theoretical

amount. The reaction mixture was filtered and the residue

was washed with ethyl ether. The total filtrate was concen-

trated on a rotary evaporator under reduced pressure to

yield 37 mg (59%) of 2-(2,4,6-cycloheptatrien-l-yl)naphtha-

lene which had all the properties of the pyrolysis product.

The sodium salt of 0-naphthaldehyde was photolyzed in a

manner analogous to the above salt to yield 67% of 2-(2,4,6-

cycloheptatrien-1-yl)naphthalene.


Preparation of 2-naphthaldazine.--The compound was

prepared by the general procedure given in "Organic Synthesis"''"

and it had mp 235-2360. Lit. 2310.0


Pyrolysis of the Sodium Salt of B-Naphthaldehyde Tosyl-

hydrazone in Cyclohexene.--To a 3 oz Fischer-Porter Aerosol

Compatibility Tube containing 15 ml of distilled cyclohexene

was added 0.40 g (1.15 mmol) of the sodium salt of B-naphth-

aldehyde tosylhydrazone. The sealed tube was placed in an

oil bath preheated to 1350 and allowed to remain for 70 min

while the temperature was raised to 1450. Upon cooling, the







mixture was filtered and the residue was washed with ethyl

ether. The total filtrate was concentrated on a rotary

evaporator to yield 212 mg of an oil. Analysis by vpc indi-

cated there were three volatile components which were sepa-

rated by preparative vpc (column A): (cyclohexene-3-yl)-2-

naphthylmethane (34%) retention time 30 min, syn-2-(7-nor-

caryl)naphthalene- (26%) retention time 32 min, and anti-2-

(7-norcaryl)naphthalenea (40%) retention time 38 min. There

was about 10% aldazine formed in the reaction but it did not

appear in the vpc chromatogram, thus the above data only

refer to volatile hydrocarbon products.

(cyclohexene-3-yl)-2-naphthylmethane showed: ir (film)

3050, 3020, 2920, 2850, 1600, 1500, 1445, 855, 820, 750 cm-1;

nmr (CDClI) T 2.00-2.90 (m, 7H, naphthyl), 4.40 (s, 2H, vinyl),

7.35 (s, 2H, methylene), 7.80-9.20 (m, 7H, cyclohexyl); mass

spectrum 222 (M+).

Anal. Calcd. for C17H16: C, 91.84; H, 8.16. Found:

C, 91.64; H, 8.20.

syn-2-(7-norcaryl)naphthalene showed: mp 68-700;

ir (melt) 3050, 3000, 2930, 2860, 1600, 1500, 1445, 830, 750,
-i
725 cm 1; nmr (CDCI3) T 2.00-2.80 (m, 7H, naphthyl), 6.60-

9.50 (m, 11H, norcaryl); mass spectrum 222 (M+).

Anal. Calcd. for C17Hia: C, 91.84; H, 8.16. Found:

C, 91.83; H, 8.20.

anti-2-(7-norcaryl)naphthalene showed: ir (film) 3050,

3005, 2925, 2850, 1625, 1598, 1505, 1442, 809, 778, 740 cm"-1

nmr (CDC13) T 2.20-3.10 (m, 7H, naphthyl), 7.90-9.30 (m, 11H,

norcaryl); mass spectrum 222 (M+).








Anal. Calcd. for C17Hi8: C, 91.84; H, 8.16. Found:

C, 91.56; H, 8.09.


Pyrolysis of the Sodium Salt of 4,5-Benzotropone Tosyl-

hydrazone in Cyclohexene at 830.--Into a 50 ml three-neck,

round-bottom flask fitted with a thermometer, condenser with

a drying tube, and a solid-addition funnel, was placed 25 ml

of distilled cyclohexene. The cyclohexene was heated to

reflux and 0.10g (0.29 mmol) of the sodium salt of 4,5-

benzotropone tosylhydrazone was added by means of the solid-

addition funnel. The mixture was heated at reflux for 4 hr

and then stopped even though the reaction was incomplete as

indicated by the presence of an orange color in the reaction

flask. The reaction mixture was filtered and the residue

was washed with ethyl ether. The total filtrate was concen-

trated on a rotary evaporator under reduced pressure. The

remaining oil was subjected to vpc analysis (column A) which

indicated five volatile components. The ratio of products

was two unknown products (66%), the naphthylcarbene-cyclo-

hexene insertion product (7%), syn-norcarane (12%), and anti-

norcarane (15%). While neither of the unknown products has

been completely characterized, one appears to be the adduct

that would result from the addition of benzocycloheptatrien-

ylidene to cyclohexene. The compound showed ir (film)
-l
3010, 2920, 2580, 1585, 1480, 1440, 795, 745, 700 cm-1; nmr

(CDC13) T 2.75 (d, 4H), 3.25 (d, IH), 3.60 (d,lH), 4.50 (d,

1H), 4.66 (d, 1H), 8.70 (broad m, 10H); mass spectrum 222 (M+);







uv (95% C2HsOH) 240 mi (log E = 4.2), 265 (3.5).

Anal. No satisfactory analysis was obtained (probably

due to insufficient sample size).


Pyrolysis of the Sodium Salt of 4,5-Benzotropone Tosyl-

hydrazone in Cyclohexene at 1400.--Into a 3 oz Fischer-Porter

Aerosol Compatibility Tube containing 15 ml of distilled

cyclohexene was introduced 0.40 g (1.15 mmol) of the sodium

salt of 4,5-benzotropone tosylhydrazone. The tube was

immersed in an oil bath preheated to 1350 and allowed to

remain for 70 min while the temperature was increased to 1450.

The mixture was allowed to cool and was filtered. The residue

was washed with ethyl ether and the total filtrate concentrated

on a rotary evaporator under reduced pressure to yield 150 mg

(58%) of products. Analysis by vpc (column A) indicated the

same five products as the 830 pyrolysis: the two "unknown"

products, the insertion product, the syn-norcarane, and the

anti-norcarane. The amount of unrearranged-carbene products

relative to the naphthyl products was approximately the same

as in the 830 pyrolysis.


Pyrolysis of the Sodium Salt of 4,5-Benzotropone Tosyl-

hydrazone in Cyclohexene--Diglyme at 820.--Into a 3 oz

Fischer-Porter Aerosol Compatibility Tube containing 17.5 g

(0.13 mol) of dry diglyme and 4.95 g (0.06 mol) of distilled

cyclohexene was introduced 0.10 g (0.29 mmol) of the sodium

salt of 4,5-benzotropone tosylhydrazone. The sealed tube

was placed in an oil bath preheated to 820 and allowed to








stir for 11 hr. The reaction mixture was allowed to cool and

poured into water (100 ml), extracted with pentane (three 35

ml portions), and the combined pentane extracts washed with

water (three 75 ml portions). The pentane solution was dried

(MgS04) and concentrated on a rotary evaporator under reduced

pressure to yield 105 mg of products. Analysis of volatile

hydrocarbon products by vpc (column A) indicated the "un-

known" products, the insertion product, the syn-norcarane,

and the anti-norcarane. There were also diglyme insertion

products amounting to 27% of the total products. Interfering

materials prevented accurate analysis of the mixture.


Photolysis of 4,5-Benzotropone Tosylhydrazone Sodium

Salt in Cyclohexene.--To the photolysis vessel, previously

described in the photolysis of 4,5-benzotropone tosylhydrazone

sodium salt in diglyme, containing 60 ml of distilled cyclo-

hexene was added 200 mg (0.58 mmol) of the sodium salt of 4,5-

benzotropone tosylhydrazone. The mixture was stirred and

irradiated with a 550 watt Hanovia medium pressure mercury

lamp for 1.25 hr. The photosylate was filtered, and the fil-

trate was concentrated on a rotary evaporator at reduced pres-

sure to yield 67 mg of product. Analysis by vpc (column A)

of the volatile hydrocarbon products indicated the "unknown"

products, a new, additional unknown product, the insertion

product, the syn-norcarane, and the anti-norcarane. The

amount of unrearranged-carbene products relative to the

naphthyl products appeared to be greater than in the pyrolyses.







Pyrolysis of the Sodium Salt of 4,5-Benzotropone Tosyl-

hydrazone in Cyclohexane.--In a 3 oz Fischer-Porter Aerosol

Compatibility Tube containing 20 ml of cyclohexane was placed

0.40 g (1.1 mmol) of the sodium salt of 4,5-benzotropone

tosylhydrazone. The sealed tube was placed in an oil bath

which was preheated to 1150 and allowed to remain for 1.25 hr.

Nitrogen evolution was 100% of the theoretical amount. The

reaction mixture was allowed to cool and then filtered. The

residue was washed with ethyl ether and the total filtrate

concentrated on a rotary evaporator under reduced pressure.

The remaining yellow oil was chromatographed on alumina,

eluted with pentane, yielding 131 mg (51%) of (B-naphthyl)

cyclohexylmethane. The nmr spectrum of the crude material

indicated almost exclusively adduct and cyclohexane. An

analytical sample of the compound was purified by preparative

vpc (column A at 2220) retention time 32 min and had the

following properties: ir (film) 3042, 3010, 2920, 2845, 1601,
-l
1445, 815, 795 cm1 ; nmr (CDCIa) r 2.10-2.90 (m, 7H, naphthyl),

7.35 (d, 2H, J=7, benzylic), 8.10-9.20 (m, 11H, cyclohexyl);

mass spectrum 224 (M+), 141 (C11H9), 83 (C6H11).

Anal. Calcd. for C17H20: C, .91.01; H, 8.99. Found:

C, 90.84; H, 8.94.


Reaction of the Sodium Salt of 4,5-Benzotropone Tosyl-

hydrazone with Dimethyl Fumarate at 105S.--Into a 3 oz

Fischer-Porter Aerosol Compatibility Tube containing 20 ml

of benzene were placed 0.20 g (0.58 mmol) of the sodium salt

of 4,5-benzotropone tosylhydrazone and 83 mg (0.58 mmol) of







dimethyl fumarate (previously washed with saturated aqueous

sodium bicarbonate and then recrystallized from chloroform).

The sealed tube was placed in an oil bath preheated to 1050

and allowed to remain for 5 hr. Upon cooling, the mixture

was filtered. The residue was washed with ethyl ether and

the total filtrate concentrated on a rotary evaporator under

reduced pressure to yield 76 mg (63%) of 2-(2,4,6-cyclohepta-

trien-l-yl)naphthalene. The nmr spectrum of the crude reac-

tion material indicated the above mentioned adduct and a con-

siderable amount of unreacted dimethyl fumarate. Comparative

tic on silica gel eluted with 50/50 ethyl ether--pentane of

the known pyrazoline videe infra) and this reaction mixture

indicated no pyrazoline was present in the latter.


Reaction of the Sodium Salt of B-Naphthaldehyde Tosyl-

hydrazone with Dimethyl Fumarate at 1050.--To a 3 oz Fischer-

Porter Aerosol Compatibility Tube containing 20 ml of benzene

was added 0.20 g (0.58 mmol) of the sodium salt of B-naphth-

aldehyde tosylhydrazone and 83 mg (0.58 mmol) of dimethyl

fumarate (previously washed with saturated aqueous sodium

bicarbonate and recrystallized from chloroform). The sealed

tube was placed in an oil bath preheated to 1050 and was

allowed to remain there for 5 hr. Upon cooling, the reaction

mixture was filtered. The residue was washed with ethyl

ether and the total filtrate was concentrated on a rotary

evaporator yielding 90 mg (50%) of an almost colorless, very

viscous oil. The oil was not stable to ordinary distillation

conditions and even though column chromatography on silica gel







effected some purification, it was not sufficient to provide

a sample which gave a good elemental analysis (e.g. Calcd.

N, 8.97; found: N, 8.31). The other physical data were all

consistent with the 3,4-dicarbomethoxy-5-naphthyl-2-pyrazoline

structure: ir (film) 3440 (N-H), 3050, 2945, 1730 (unconju-

gated ester carbonyl), 1700 (conjugated ester carbonyl), 1555

(C=N), 1440, 1200, 1015, 855, 815, and 750 cm-1; nmr (CDC13)

T 2.10-2.60 (m, 7H, naphthyl), 3.24 (broad s, IH, nitrogen),

4.60 (broad d, 1H, J=9, benzylic), 5.92 (d, 1H, J=9, a-carbo-

methoxy), 6.18 (s, 3H, conjugated ester methyl), 6.24 (s, 3H,

unconjugated ester methyl)*; mass spectrum no (M+), 284 (M -

28); uv (95% C2HsOH) 224 mp (log c = 4.53), 275 (3.75), 287

(3.79).


Reaction of g-Naphthaldehyde Tosylhydrazone Sodium Salt

with Dimethyl Fumarate at 1600.--This decomposition was

carried out in the same manner as the low temperature one

with the exception that the sealed tube was placed in an oil

bath preheated to 1050 and allowed to remain for 2 hr while

the temperature was raised to 1600. Upon cooling, the mixture

was filtered. The filter paper and the residue were washed

with ethyl ether and the total filtrate concentrated on a

rotary evaporator under reduced pressure to yield 110 mg (67%)


In addition there were other resonances which changed in

intensity depending upon work up and purification steps

and are, therefore, not believed to originate from the

pyrazoline.








of crude trans-1,2-dicarbomethoxy-3-(2-naphthyl)cyclopropane.

The solid was recrystallized from abs methyl alcohol to yield

35 mg (21%) of pink needles mp 91-930: ir (CC14) 3028, 2975,

1730, 1435, 1300, 1170, and 909 cm-1; nmr (CDC13) T 2.00-2.90

(m, 7H, naphthyl), 6.23 (s, 3H, methyl), 6.58 (s, 3H, methyl),

6.70-7.50 (m, 3H, cyclopropane ring); mass spectrum 284 (M+).

Anal. Calcd. for C17H1i6O : C, 71.82; H, 5.67; 0, 22.51.

Found: C, 71.93; H, 5.73; 0, 22.34.


Reaction of the Sodium Salt of 4,5-Benzotropone Tosyl-

hydrazone with Dimethyl Fumarate at 1600.--This decomposition

was carried out in the same manner as the low temperature one

with the exception that the sealed tube was placed in an oil

bath preheated to 1050 and allowed to remain for 2 hr while

the temperature was raised to 1600. Upon cooling, the mixture

was filtered. The residue was washed with ethyl ether and

the total filtrate concentrated on a rotary evaporator under

reduced pressure. The products were not isolated, only cur-

sorily examined by nmr spectroscopy. The materials, 2-(2,4,6-

cycloheptatrien-l-yl)naphthalene and 2-(2,4,6-cycloheptatrien-

4-yl)naphthalene, were readily identified by their character-

istic spectra and determined to be present in a ratio of

1.0:1.6, respectively, as shown by integration.


General Procedure for the Photolysis of Tosylhydrazone

Sodium Salts in the 2-Butenes.--The photolyses were carried

out in an apparatus which consisted of a Pyrex tube (20 cm x

2.5 cm) with two side arms and equipped with a small mechanical







stirrer. One of the side arms was connected to a Dry Ice

condenser with a drying tube and the other to a stopcock.

The desired amount of tosylhydrazone salt was introduced into

the apparatus which was consequently flushed with dry nitro-

gen. The apparatus was then placed in a small Dry Ice-acetone

bath and the 2-butene condensed into the vessel. The vessel

was then mounted vertically alongside, and as close as pos-

sible to,a 550 watt Hanovia medium pressure mercury lamp in

a Pyrex cooling jacket. Both the apparatus and the lamp

system were placed in a large Dewar flask containing methyl

alcohol, with the temperature of the entire system being

regulated by the cooling jacket of the lamp which in turn was

cooled by a Dry Ice-acetone heat exchanger. The mixture was

then rapidly stirred and irradiated for the desired amount of

time at temperatures in the range of -15 to -30.


Photolysis of the Sodium Salt of B-Naphthaldehyde Tosyl-

hydrazone in trans-2-Butene.--Into the previously described

photolysis apparatus was placed 0.20 g (0.58 mmol) of the

sodium salt of 8-naphthaldehyde tosylhydrazone and 30 ml of

trans-2-butene (C.P. Grade, typical analysis 99.3 mole %

trans-2-butene, 0.2 mole % butene, and 0.5 mole % cis-2-

butene). The reaction mixture was irradiated for 2.0 hr at

temperatures between -15 to -200. At the end of this time,

the butene was allowed to evaporate and the residue was

dissolved in ethyl ether, filtered, and concentrated on a

rotary evaporator under reduced pressure to yield 88 mg of a








light yellow oil. In addition to a small amount of unknown

products, the material contained three products, l-(2-naphthyl)-

trans-2,3-dimethylcyclopropane, and syn- and anti-l-(2-

naphthyl)-cis-2,3-dimethylcyclopropane, as shown by vpc

analysis. The trans-cyclopropane was analyzed (column A) and

purified by prep vpc (column A).

1-(2-naphthyl)-trans-2,3-dimethylcyclopropane showed:

ir (film) 3050, 3000, 2940, 2920, 2860, 1628, 1600, 1500,
-l
1450, 1058, 850, 815, 745 cm-1; nmr (CCl4) T 2.10-2.95

multiplee, 7H, naphthyl protons), 8.15 multiplee, 1H, proton

on C-l), 8.35-9.65 multiplee, 8H, protons on C-2 and C-3

and methyl protons); mass spectrum m/e 196 (M+).

Anal. Calcd. for C15H16: C, 91.78; H, 8.22. Found:

C, 91.72; H, 8.31.


Photolysis of Benzaldehyde Tosylhydrazone Sodium Salt in

trans-2-Butene.--In the described photolysis apparatus was

placed 0.40 g (1.35 mmol) of the sodium salt of benzaldehyde

tosylhydrazone,38 then 25 ml of trans-2-butene (C.P. Grade)

was condensed into the apparatus. The reaction mixture was

irradiated for 2.5 hr at temp between -150 and -200. At the

end of this time, the butene was allowed to evaporate and the

residue was dissolved in ethyl ether, filtered, and concen-

trated on a rotary evaporator under reduced pressure to yield

0.09 g (45%) of crude 1-phenyl-trans-2,3-dimethylcyclopropane.

The cyclopropane was purified by preparative vpc (column A).

The nmr (CDClI) T 2.93 (broad singlet, 5H, phenyl protons),







8.30 multiplee, 1H, proton on C-1), 8.68-9.36 multiplee,

8H, protons on C-2 and C-3 and methyl protons) agreed with

the data of Closs.43


Photolysis of the Sodium Salt of 6-Naphthaldehyde Tosyl-

hydrazone in cis-2-Butene.--The photolysis of the sodium salt

of 8-naphthaldehyde tosylhydrazone in cis-2-butene was carried

out in a manner similar to that of trans-2-butene. In this

case, 0.29 g (0.84 mmol) of the sodium salt was decomposed in

30 ml cis-2-butene (C.P. Grade, typical analysis 99.5 mole %

cis- and 0.5 mole % trans-2-butene) and the photolysis was

done over a period of 2.75 hr at a temp between -200 and -300.

There was produced 0.126 g of a light yellow oil. Again the

products were analyzed by vpc and the same three products

were present (relative yields): l-(2-naphthyl)-trans-2,3-

dimethylcyclopropane (3%), syn- and anti-l-(2-naphthyl)-cis-

2,3-dimethylcyclopropane (97%). The syn- and anti-cyclopro-

panes were purified by preparative vpc (column A).

syn-l-(2-naphthyl)-cis-2,3-dimethylcyclopropane showed:

ir (film) 3050, 3000, 2940, 2870, 1630, 1602, 1500, 1385,

1160, 890, 860, 818, 748 cm-1; nmr (CC1I) r 2.20-3.00 (multi-

plet, 7H, naphthyl protons), 7.90 multiplee, 1H, proton on

C-l), 8.50-9.50 multiplee, 8H, protons on C-2 and C-3 and

methyl protons); mass spectrum m/e 196 (M+).

Anal. Calcd. for C1sH16: C, 91.78; H, 8.22. Found:

C, 91.55; H, 8.15.







anti-l-(2-naphthyl)-cis-2,3-dimethylcyclopropane showed:

ir (film) 3050, 3000, 2940, 2860, 1628, 1600, 1500, 1082,

850, 815, 782, 745 cm-1; nmr (CC14) T 2.20-3.10 multiplee,

7H, naphthyl protons), 8.50-9.15 multiplee, 9H, protons on

C-1, 2, and 3 and methyl protons); mass spectrum m/e 196 (M+).

Anal. Calcd. for C1sH16: C, 91.78; H, 8.22. Found:

C, 91.63; H, 8.29.


Pyrolysis of B-Naphthaldehyde Tosylhydrazone Sodium Salt

in cis-2-Butene.--In a 0.5 oz reusable Fischer-Porter Carius

Tube was placed 0.10 g (0.29 mmol) of the sodium salt of

B-naphthaldehyde tosylhydrazone. The tube was fitted with a

Dry Ice condenser by means of a rubber stopper, flushed with

dry nitrogen, and placed in a Dry Ice-acetone bath. Then 10

ml of trans-2-butene was condensed into the Carius Tube; the

condenser was quickly removed and the tube sealed. The tube

was then immersed in an oil bath (preheated to 1050) for 1 hr.

At the end of this time the tube was allowed to cool to room

temperature and then cooled further in a Dry Ice-acetone

bath. The tube was opened, the bath removed, and the butene

allowed to evaporate. The residue was dissolved in ethyl

ether, concentrated on a rotary evaporator at reduced pres-

sure, and analyzed by vpc (column C) to yield the following

data (relative yields): l-(2-naphthyl)-trans-2,3-dimethyl-

cyclopropane (-10%),* and syn- and anti-l-(2-naphthyl)-cis-

2,3-dimethylcyclopropane (-90%).


A large amount of interfering material makes this data

only approximate.







Photolysis of 4,5-Benzotropone Tosylhydrazone Sodium

Salt in cis-2-Butene.--The photolysis of the sodium salt of

4,5-benzotropone tosylhydrazone was effected using 0.29 g

(0.84 mmol) of the salt in 30 ml of cis-2-butene (C.P. Grade)

and by irradiating for 2.3 hr at -250. Work up yielded 0.061

g of product and vpc analysis (column C) gave the following

data: 1-(2-naphthyl)-trans-2,3-dimethylcyclopropane was a

minor product (4%); the major products were syn-l-(2-naphthyl)

cis-2,3-dimethylcyclopropane and anti-l-(2-naphthyl)-cis-2,3-

dimethylcyclopropane (96%).


Photolysis of 4,5-Benzotropone Tosylhydrazone Sodium

Salt in trans-2-Butene.--The photolysis of the sodium salt of

4,5-benzotropone tosylhydrazone was effected as previously

described using 0.20 g (0.58 mmol) of the salt in 30 ml of

trans-2-butene (C.P. Grade) and by irradiating for 2.3 hr at

-250. Work up yielded 0.046 g of a yellow oil. Vpc analysis

(column C) gave the following data: 1-(2-naphthyl)-trans-

2,3-dimethylcyclopropane was the major product along with a

small amount of the epimeric l-(2-naphthyl)-cis-2,3-dimethyl-

cyclopropanes.


Pyrolysis of the Sodium Salt of 4,5-Benzotropone Tosyl-

hydrazone in cis-2-Butene.--In a 0.5 oz reusable Fischer-

Porter Carius Tube was placed 0.10 g (0.29 mmol) of the

sodium salt of 4,S-benzotropone tosylhydrazone. The tube was

fitted with a Dry Ice condenser by means of a rubber stopper,

flushed with dry nitrogen, and placed in a Dry Ice-acetone







bath. Then, 10 ml of cis-2-butene (research grade) was con-

densed into the Carius Tube; the condenser was quickly removed

and the tube sealed. The tube was allowed to warm to room

temperature and then immersed in an oil bath (preheated to

1050) for 3.5 hr. At the end of this time the tube was

allowed to cool to room temperature and then cooled further

in a Dry Ice-acetone bath. The tube was opened, the bath

removed, and the butene allowed to evaporate. The residue

was dissolved in ethyl ether, concentrated on a rotary evapo-

rator under reduced pressure to yield 7 mg of a yellow oil

which was analyzed by vpc (column C). The reaction material

contained the syn- and anti-l-(2-naphthyl)-cis-2,3-dimethyl-

cyclopropanes (93%), l-(2-naphthyl)-trans-2,3-dimethylcyclo-

propane (7%), and some extraneous material. In all cases

following the percentages given in parentheses do not imply

total percent yield but relative yields of the cis- and trans-

cyclopropanes and were done on column C unless otherwise

stated.


Pyrolysis of the Sodium Salt of 4,5-Benzotropone Tosyl-

hydrazone in cis-2-Butene and Benzene.--The reaction was

carried out as in the above experiment except that 0.08 g

(0.23 mmol) of the sodium salt, 7.0 ml (79 mmol) of benzene,

and 2.5 ml (28 mmol) of research grade cis-2-butene were

heated at 1050 for 3 hr. The work up was the same yielding

10 mg of a yellow oil which contained the cyclopropanes in

the following relative yield: syn- and anti-l-(2-naphthyl)-

cis-2,3-dimethylcyclopropanes (94%) and 1-(2-naphthyl)-trans-







2,3-dimethylcyclopropane (6%). The 2-naphthylcarbene-benzene

adduct was also produced as evidenced by vpc.


Pyrolysis of the Sodium Salt of 4,5-Benzotropone Tosyl-

hydrazone in cis-2-Butene and Perfluorocyclobutane.--Again,

the reaction was carried out in a manner analogous to that of

the cis-2-butene reaction. In this series two reactions were

carried out: the first with cis-2-butene and perfluorocyclo-

butane in a 1:2 molar ratio, respectively, and the second

with a 1:6 molar ratio, respectively.

In the first reaction, 0.10 g (0.29 mmol) of the sodium

salt of benzotropone tosylhydrazone, 8.0 ml (60 mmol) of per-

fluorocyclobutane, and 2.5 ml (30 mmol) of research grade cis-

2-butene were heated at 1050 for 5 hr. The work up yielded

7.5 mg of a yellow oil which, when analyzed by vpc, was shown

to contain the syn- and anti-l-(2-naphthyl)-cis-2,3-dimethyl-

cyclopropanes (94%) and 1-(2-naphthyl)-trans-2,3-dimethyl-

cyclopropane (6%).

In the second case, 0.10 g (0.29 mmol) of the sodium

salt of benzotropone tosylhydrazone, 9.0 ml (67 mmol) of

perfluorocyclobutane, and 1.0 ml (11 mmol) of research grade

cis-2-butene were heated at 1080 for 4 hr. The work up

yielded 7.0 mg of a yellow oil which gave the same cis to

trans cyclopropane ratio as the first experiment (namely,

cis 94% and trans 6%).







Pyrolysis of the Sodium Salt of 4,5-Benzotropone Tosyl-

hydrazone in cis-2-Butene and Oxygen.--This reaction, too,

was carried out like the cis-2-butene reaction with the fol-

lowing exceptions: 0.10 g (0.29 mmol) of the sodium salt of

benzotropone tosylhydrazone and 12 ml of research grade cis-

2-butene were placed in the Carius Tube and then oxygen was

bubbled through the mixture for 1 hr. The reaction mixture

was heated at 1080 for 3.6 hr and the work up yielded 21 mg

of a yellow oil which contained the two epimeric cis-cyclo-

propanes (96%) and the trans-cyclopropane (4%).

A control experiment, done exactly the same as the above

experiment only bubbling nitrogen through the mixture, gave

the typical 94% cis- material and 6% trans-.


Pyrolysis of the Sodium Salt of 4,S-Benzotropone Tosyl-

hydrazone in cis-2-Butene and trans,trans-2,4-hexadiene.--

Again, the reaction was carried out in a manner analogous to

that of the cis-2-butene reaction. In this series two sepa-

rate reactions were carried out: the first with cis-2-butene

and trans,trans-2,4-hexadiene in a 1.0:1.5 molar ratio, respec-

tively, and the second with a 1.0:2.1 molar ratio, respectively.

In the first reaction, 0.09 g (0.26 mmol) of the sodium

salt of benzotropone tosylhydrazone, 7.0 ml (60 mmol) of

trans,trans-2,4-hexadiene, and 3.6 ml (40 mmol) of research

grade cis-2-butene were heated at 1050 for 4.5 hr. Work up

yielded 24 mg of product (again, a yellow oil) which had the

cis-cyclopropanes produced in 99% yield relative to the trans-







cyclopropane in 1%. However, what is assumed to be the

products from the diene account for ca. 90% of the total

products.

In the second case, 0.10 g (0.29 mmol) of the sodium

salt of benzotropone tosylhydrazone, 7.3 ml (63 mmol) of

trans,trans-2,4-hexadiene, and 2.7 ml (30 mmol) of research

grade cis-2-butene were heated at 1050 for 5 hr. Work up

yielded 18 mg of a yellow oil which proved to be almost

exclusively the assumed diene products (there was too little

of the butene adducts to provide reliable results).


Sensitized Photolysis of the Sodium Salt of 4,5-Benzo-

tropone Tosylhydrazone in Benzene.--In the photolysis vessel,

described previously, was placed 1.0 g (5.1 mmol) xanthen-9-

one, 0.10 g (0.29 mmol) of the sodium salt of benzotropone

tosylhydrazone, and 40 ml of benzene. The stirred mixture

was photolyzed at 300 for I hr. The solvent was evaporated

and the residue was chromatographed on grade III Woelm basic

alumina. There were no hydrocarbon products isolated from

the reaction mixture.


Thermal Stability of the syn- and anti-l-(2-naphthyl)-

cis-2,3-dimethylcyclopropanes.--A sample of the cis-cyclopro-

panes was preparatively chromatographed (column A at 2300)

and then analyzed for any isomerization during chromatography.

There was no trace of trans-cyclopropane as evidenced by vpc

analysis (column B).







Stability of cis-2-Butene under Reaction Conditions.--As

in a typical run, 0.10 g (0.29 mmol) of the sodium salt of

benzotropone tosylhydrazone and 9.0 ml cis-2-butene (research

grade) were heated in a Carius Tube at 1050 for 4.25 hr.

Analysis of the cis-2-butene (column C) after the usual

reaction period indicated that less than 1 percent isomeri-

zation had occurred during the reaction.


2-Methyl-4,5-Benzotropone.--The ketone was prepared by

the method of Heilbronner and had a mp 68-690. Lit. 700.52


2-Methyl-4,5-Benzotropone Tosylhydrazone.--In a typical

run, 2.00 g (0.012 mol) of 2-methyl-4,5-benzotropone, 2.18 g

(0.012 mol) of p-toluenesulfonylhydrazide, and 5 drops of

coned sulfuric acid were placed in 40 ml of abs ethyl alcohol

and heated at reflux for 1 hr. Upon cooling, 2-methyl-4,5-

benzotropone tosylhydrazone precipitated from solution and

was isolated by filtration. Recrystallization from abs ethyl

alcohol yielded 2.4 g (60%) of the product as yellow-gold

plates mp 182-1840: ir (KBr) 3180, 1630, 1590, 1555, 1420,

1385, 1330, 1165, 1022, 915, 805, 760, 680, and 580 cm-1;

nmr (CDC13) T 2.00-3.00 (A2B2, 4H, J=8, aromatic), 2.78 (s,

4H, benzo), 3.05-3.70 (m, 3H, cycloheptatrienyl), 7.62 (s,

3H, p-methyl), 7.88 (d, 3H, cycloheptatrienyl methyl); mass

spectrum 339 (M+).

Anal. Calcd. for C19iHiN202S: C, 67.43; H, 5.36; N,

8.28. Found: C, 67.39; H, 5.33; N, 8.40.







Pyrolysis of the Sodium Salt of 2-Methyl-4,5-Benzotropone

Tosylhydrazone in Benzene.--To a Fischer-Porter Aerosol Com-

patibility Tube containing 35 ml of benzene was added 216 mg

(0.60 mmol) of the sodium salt of 2-methyl-4,5-benzotropone

tosylhydrazone. The sealed tube was placed in an oil bath

preheated to 1300 for 20 min. By the end of this time the

yellow mixture had changed to a very light yellow-green one.

The mixture was allowed to cool and was filtered. The residue

was washed with ethyl ether and the total filtrate concen-

trated on a rotary evaporator under reduced pressure to yield

80 mg of products. Analysis of the product mixture by nmr

indicated the presence of 2-vinylnaphthalene and 2-(2,4,6-

cycloheptatrien-l-yl)-3-methylnaphthalene (comparisons were

made using commercially available 2-vinylnaphthalene from

Aldrich Chemical Co. and 2-(2,4,6-cycloheptatrien-l-yl)-3-

methylnaphthalene from the pyrolysis of the sodium salt of

the tosylhydrazone of 3-methyl-2-naphthaldehyde in benzene).

Analysis by vpc (column B) indicated three products in the

reaction mixture (the known ones were established by compari-

son with known samples): 1) retention time 1 min, 2-vinyl-

naphthalene (72%); 2) retention time 10 min, unknown compound

(6%); 3) retention time 14 min, 2-(2,4,6-cycloheptatrien-l-

yl)-3-methylnaphthalene (22%). Products 1 and 3 were isolated

in 44% and 20% overall yield, respectively. 2-(2,4,6-cyclo-

heptatrien-l-yl)-3-methylnaphthalene sublimedd at 900 and

0.1 mm Hg) had the following properties: mp 65-680; ir (KBr)

3055, 3010, 1600, 1500, 1440, 1220, 1010, 890, 745, 700, and








480 cm-1; nmr (CDC13) T 2.00-2.90 (m, 6H, naphthyl), 3.25

(broad t, 2H, 4 and S cycloheptatrienyl), 3.50-3.90 (complex

pattern, 2H, 3 and 6 cycloheptatrienyl), 4.35-4.76 (complex

pattern, 2H, 2 and 7 cycloheptatrienyl), 6.95 (broad t, IH,

methine), 7.65 (s, 3H, methyl); mass spectrum 232 (M+).

Anal. Calcd. for Cs1H16: C, 93.06; H, 6.94. Found:

C, 92.85; H, 7.00.

The sodium salt of 3-methyl-2-naphthaldehyde tosylhydra-

zone was pyrolyzed in the same manner as the above salt

except that 40 ml of benzene was used and the temperature

was 1450. The products were aldazine (42%) and 2-(2,4,6-

cycloheptatrien-l-yl)-3-methylnaphthalene (39%).


2,3-Benzotropone.--2,3-Benzotropone was prepared by the

method of Collington and Jones,53 and the ir spectrum of the

product was in complete agreement with that reported in the

literature.


2,3-Benzotropone Tosylhydrazone.--To 1.0 g (0.6 mol) of

2,3-benzotropone in 10 ml of 95% ethyl alcohol was added

1.1 g (0.6 mol) of g-toluenesulfonylhydrazide in 25 ml of 95%

ethyl alcohol and one drop of acetic acid. The solution was

heated at reflux for 75 min, and then the reaction mixture

was allowed to cool. The solvent was removed on a rotary

evaporator under reduced pressure and the resinous residue

was chromatographed on silica gel eluting with methylene

chloride. The thus purified tosylhydrazone, still a viscous

resin, was obtained 54% yield and had the following properties:







ir (film) 3210, 1582, 1400, 1385, 1340, 1320, 1160, 1080,

1020, 810, 800, 760, 700, 680, 655 cm-1; nmr (CDCl3) T 1.60

(broad s, 1H, proton on nitrogen), 2.00-4.00 multiplee, 12H,

protons on benzo ring, cycloheptatriene ring, and the aromatic

toluyl protons whose A2B2 quarter could be picked out of the

multiple, 7.70 (s, 3H, methyl).

The tosylhydrazone was never obtained in a state of

purity which gave a good analysis (e.g. Calcd. C, 65.38;

H, 5.16. Found: C, 65.10; H, 5.84). Mass spectrum had no

parent peak, (none of any significance above m/e 156 even at

10 eV) 156 (100), 141 (9), 91 (17), 64 (28).

The resinous tosylhydrazone was converted to its sodium

salt cleanly by the outlined procedure (this was the only

water-sensitive salt made).


Pyrolysis of the Sodium Salt of 2,3-Benzotropone Tosyl-

hydrazone in Benzene.--In a 3 oz Fischer-Porter Aerosol

Compatibility Tube containing 35 ml of benzene (deoxygenated

by bubbling in nitrogen for several min) was placed 0.28 g

(0.81 mmol) of the sodium salt of 2,3-benzotropone tosylhydra-

zone. The tube was then placed in an oil bath which was pre-

heated to 1200 and allowed to remain there for 35 min. The

solution was allowed to cool, filtered, and concentrated to

a yellow oil on a rotary evaporator under reduced pressure.

Chromatography of the residue on activity grade III basic

Woelm alumina yielded 0.045 g (26%) of a colorless oil which

was identified as l-(2,4,6-cycloheptatrien-l-yl)naphthalene.




86


The properties of the compound are as follows: ir (film)
-l
3050, 3020, 1600, 1510, 1395, 800, 780, 745, 705 cm ; nmr

(CDCla) x 2.20 multiplee, 3H, a-protons of naphthyl system),

2.55 multiplee, 4H, B-protons of naphthyl system), 3.30

(triplet, 2H, J=3 Hz, 4 and 5 protons on cycloheptatriene),

3.70 multiplee, 2H, 3 and 6 protons on cycloheptatriene),

4.50 (quartet, 2H, J=5.5 Hz, 2 and 7 protons on cyclohepta-

triene), and 6.60 multiplee, 1H, 7 proton on cyclohepta-

triene); mass spectrum m/e 218 (M+), 127 (CloH07), 91 (C7H7).

Anal. Calcd. for C17Hil: C, 93.54; H, 6.46. Found:

C, 93.32; H, 6.61.












LIST OF REFERENCES


1. L. Skattebol, Tetrahedron, 23, 1107 (1967).

2. P. Ashkenazi, S. Lupan, A. Schwarz, and M. Cais, Tetra-
hedron Lett., 817 (1969).

3. G. Frater and 0. P. Strausz, J. Amer. Chem. Soc., 92,
6654 (1970); D. E. Thornton, R. K. Gosavi, and 0. P.
Strausz, ibid., 92, 1768 (1970); I. G. Csizmadia,
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4. R. L. Russell and F. S. Rowland, ibid., 92, 7508 (1970).

5. G. G. Vander Stouw, Dies. Abst., 25, 6974 (1965) and
Chem. Abet., 63, 13126b (1965) undeer the direction of
H. Shechter.

6. G. G. Vander Stouw, A. R. Kraska, and H. Shechter, J.
Amer. Chem. Soc., 94, 1655 (1972).

7. R. C. Joines, A. B. Turner, and W. M. Jones, ibid., 91,
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8. W. M. Jones and C. L. Ennis, ibid., 91, 6391 (1969).

9. J. A. Myers, R. C. Joines, and W. M. Jones, ibid., 92,
4740 (1970).

10. C. Wentrup and K. Wilczek, Helv. Chim. Acta, 53, 1459
(1970).

11. P. O. Schissel, M. E. Kent, D. J. McAdoo, and E. Hedaya,
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12. E. Hedaya and M. E. Kent, ibid., 93, 3285 (1971).

13. W. J. Baron, M. Jones, Jr., and P. P. Gaspar, ibid., 92,
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14. T. Mitsuhashi and W. M. Jones, ibid., 94, 677 (1972).

15. P. H. Gebert, Ph.D. Dissertation, University of Florida,
Gainesville, Florida, 1972, under the direction of
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