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THESIS

This is to certify that the

dissertation entitled

(CH)]2 HYDROCARBONS: THERMAL AND PHOTOCHEMICAL
PREPARATION, STRUCTURE DETERMINATION, AND
MECHANISTIC INVESTIGATION

presented by
MEHDI GHANDI

has been accepted towards fulfillment
of the requirements for

PH.D. CHEMISTRY

degree in

 

 

Donald G. Farnum

 

 

Major professor

8-11-81
Date

 

MS U is an Aflirmatt've Action/Equal Opportunity Institution 0-12771

M. —— ..
_ ”A.--J ”A. — '

1.323323“
wicmgam mate
University

 
 
 

 

OVERDUE FINES:
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Place in book return to remove
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(CH)l2 HYDROCARBONS: THERMAL AND PHOTOCHEMICAL
PREPARATION, STRUCTURE DETERMINATION, AND

MECHANISTIC INVESTIGATION

By

Mehdi Ghandi

A DISSERTATION

Submitted to
Michigan State University

in partial fulfillment of the requirements

for the degree of

DOCTOR OF PHILOSOPHY

Department of Chemistry

1981

.\

Irl

..Il\\\\|.,J.

 

 

 

374/

'5‘

’3',

’ /

an

,r
V’

ABSTRACT

(CH)12 HYDROCARBONS: THERMAL AND PHOTOCHEMICAL
PREPARATION, STRUCTURE DETERMINATION, AND

MECHANISTIC INVESTIGATION
By
Mehdi Ghandi

Pyrolysis of the dry trans-B-[anti-9-bicyclo[6.l.O]-
nona-2,A,6-trienyl]acrolein tosylhydrazone lithium salt I
at 250° resulted in the formation of six products, charac-
terized as: egg and endg-tricycloEA.u.2.02’5]dodeca—3,7,-

9,11-tetraenes {I and III, pentacyclo[6.u.O.O2’l2.03’7-

ou’lljdodeca-5,9-diene IX, l,2-benzocycloocta-l,3,7-triene
X, and 9-syn and anti (5-DYPazola)bicyclo[A.2.l]nona-2,h,-
7-trienes VI and VII. On the other hand, the formation of

’Vb ’VVM
diene {X as the only (CH)l2 hydrocarbon from either pyrolysis
or photolysis of trans-B-[szn-9-bicyclOEA.2.1]nona-2,A,7-
trienyIJacrolein tosylhydrazone salt XIII showed that
hydrocarbons II and III have arisen from a different

"Vb ’Vb’b

carbene intermediate than diene IX in the pyrolysis of

2
tosylhydrazone salt I. Thermolysis of anti-9-(A -cyclopro-

peno)-bicyclo[6.l.O]-nona-2,A,6-triene II resulted in the

Mehdi Ghandi

formation of a new (CH)l2 isomer, characterized as
pentacyclof6.u.0.02’u.03’10.05’9]dodeca-6,ll-diene é.
Thislatteriresult clearly ruled out the hydrocarbon I§
as the potential thermal precursor of diene IX in the

pyrolysis of tosylhydrazone salt I.

To The Heroic People of Iran

ACKNOWLEDGEMENTS

The author wishes to express his sincere appreciation
to Professor Donald G. Farnum for his guidance, encourage-
ment,understanding, and friendship throughout the course of
this study.

The author acknowledges the financial support of the

people of Iran administereti through the Free University

of Iran.

Thanks are extended to Michigan State University for
financial support as a graduate assistant during the course

of this work.

Finally, I would like to thank Ernest A. Oliver for his

excellent job on taking the GC/MS spectra.

TABLE OF CONTENTS

CHAPTER Page

LIST OF FIGURES
INTRODUCTION. . . . . . . . . . . . . . .-. . . . . 1
RESULTS AND DISCUSSION. PART A . . . . . . . . . . 21
Synthesis of Trans-B-[anti—Q-bicyclo-
[6.1.0]-nona-2,A,6-trienyl]Acrolein
Tosylhydrazone (é§) . . . . . . . . . . . . . . 21
Thermal decomposition of trans-8-
[anti-9-bicyclo[6.l.O]nona-2,A,6-
trienyIJAcrolein Tosylhydrazone Lithium
Salt (gz). Preparation of Exo-tricyclo-
[H.u.2.02’5]dodeca-3,7,9,ll-tetraene (%Q)’
Endg—tricyclo[u.u.2.02’5]dodeca-3,7,9,ll-
tetraene (2g), Pentacyclo[6.A.O.02’l2-
.03’7.Ou’lleodeca-5,9-diene (pg), 1,2-
Benzocycloocta-l,3,7-triene (é%)a 9-

syn and anti(5-pyrazola)bicyclo[u.2.1]—

nona-2,A,7—triene (SQ), (SQ). . . . . . . . . 21
Pentacyclo[6.u.0.02’12.O3’7.Ou’ll]
dodeca-5,9-diene (éé) . . . . . . . . . . . . 2h

9-syn and anti(5-pyrazola)bicyclo-

[u.2.l]nona-2,A,7-trienes (3%) and (éé) . . . 32

Chapter Page

Mechanistic Investigation of the Tosyl-

hydrazone Lithium Salt (éz) Decomposi-

tion. . . . . . . . . . . . . . . . . . . . . . 35
A Look at the Plausible Mechanism for

the Formation of Tetraenes (1%) and (2%). . . . 37
A close Look at the Mechanism to Hydro-

carbons (éé), (QA) and Pyrazoles (§%)2 (éé) . . A0
Thermolysis of anti-9-(A2-cy010propeno)-

bicyclo[6.l.O]nona-2,A,6-triene (él).

Preparation of Pentacyclo[6.u.0.02’u-
.03’10.05’gjdodeca-6,ll—dient (éé)' . . . . . . “0
Thermal Rearrangement of [6.1.0] system . . . . 53

Thermal Rearrangement of Tosylhydra-

zone (éé). Preparation of trans-8-
[sygfbicyclo[u.2.l]nona-2,A,7-trienyl]-

Acrolein Tosylhydrazone (éé). . . . . . . . . . 59
Pyrolysis of Trans-B-[syn—bicyclo-
[A.2.1]nona-2,A,7-trienyIJAcrolein

Tosylhydrazone Lithium Salt (2%).

Preparation of Diene (SS) and Pyrazole
(gig) 60
Photolysis of the Sodium Salt of Trans-
-[§yQ-bicyclo[u.2.1]nona-2,A,7-trienyl]-

Acrolein Tosylhydrazone éé' Preparation

of Diene (QQ) . . . . . . . . . . . . . . . . . 61

Chapter Page

Summary . . . . . . . . . . . . . . . . . . . . . . 65
Results and Discussion - Part B . . . . . . . . . . 67
Experimental. . . . . . . . . . . . . . . . . . . . 7A
General . . . . . . . . . . . . . . . . . . . . . . 7U

9-Carbethoxy bicyclo[6.l.O]-2,A,6-

triene (ég) . . . . . . . . . . . . . . . . . . 75
9-Hydroxymethylbicyclo[6.1.0]nona-2,A,6-

trient (69) . . . . . . . . . . . . . . . . . . 75
Bicyclo[6.l.O]nona-2,A,6-triene—9-

Carboxaldehyde (61) . . . . . . . . . . . . . . 75
Diethyl 2,2-diethoxyethyl Phosphonate

(ISQ) . . . . . . . . . . . . . . . . . . . . . 76
Diethyl Formylmethyl Phosphonate (lég) .. . . . 76
Diethyl 2-(cyclohexylamino)vinyl Phos-

phonate (IAQ) . . . . . . . . . . . . . . . . . 76
Trans-B-[agti-Q—bicyclo[6.1.0]nona-
2,A,6-trienyl]Acrolein (62) . . . . ... . . . . 77
Trans-B-[anti—9-bicycloE6.1.0]nona-2,U,6-
trienyIJAcrolein Tosylhydrazone (6%). . . . . . 77
Preparation of Tosylhydrazone Lithium

Salt (57) . . . . . . . . . . . . . . . . . . . 78
Pyrolysis of Tosylhydrazone Lithium

Salt 57. Preparation of Exp-tricyclo
EA.A.2.02’5]dodeca-3,7,9,ll-tetraene

(IA), Endo—tricyclo[u.u.2.O2’5]dodeca-

Chapter Page

3,7,9,ll-tetraene (5%), Pentacyclo—

[6.14.0.0‘2’l2p3’7.01"ll

Jdodeca-5,9—

diene (58), 1,2—Benzocycloocta-l,3,7-

triene (63), and 9-syn and anti (5-

pyrazola)bicyclo[u.2.l]nona-2,A,7-

triene (5%) and (55). . . . . . . . . . . . . . 79

Spin Decoupling Studies of Diene

(g8). . . . . . . . . . . . . . . . . . . . . . 82

Agfli-9-(A2cyclopropeno)-bicyclo[6.l.O]-

nona-2,A,6-triene (51). Low Temperature

Photolysis Decomposition of Tosylhydra-

zone Sodium Salt (£2) . . . . . . . . . . . . . 85

Pyrolytic Attempts at Isomerizing

Compound (51) . . . . . . . . . . . . . . . . . 86
Method A. . . . . . . . . . . . . . . . . . 86
Method B. . . . . . . . . . . . . . . . . . 87
Method C. . . . . . . . . . . . . . . . . . 87
Method D. Preparation of Penta-

cyclo[6.A.O.O2’u.03’10.05’9]
dodeca-6,ll-diene (86). . . . . . . . . . . 88

Preparation of Trans-3-[syn-9—bicyclo

[A.2.1]nona-2,A,7-trienyl]Acrolein

Tosylhydrazone (65) . . . . . . . . . . . . . . 9O

Chapter

Preparation of Trans-B-[syn-9-bicyclo
[A.2.l]nona-2,A,7-trienylecrolein
Tosylhydrazone Lithium Salt gé. . . . .
Pyrolysis of Tosylhydrazone Lithium Salt
2%. Preparation of Diene 58 and Pyra-
zole 5% . . . . . . . . . . . .
Photolysis of Sodium Salt of Tosyl-
hydrazone 65. Preparation of Pyrazole
aa-

Photolysis of the Sodium Salt of Tosyl-
hydrazone 65 Through a Quartz Filter
Using a 200 w Hg Vapor Lamp. Preparation
of Pyrazole 5%.

Low Temperature Photolysis of the Sodium
Salt of Tosylhydrazone 65 Through a
Pyrex Filter with 200 w Hg Vapor Lamp.
Preparation of Diene 58
Pentachlorocyclopropane 13153
Tetrachlorocyclopropene 12553 . . . .
Antir9-Chlorobicyclo[6.l.O]nona-2,A,6-
triene 152. . .

Preparation of 2,3,A-Trichloropentacyclo-
[6.u.o.o2’“.o3’lo.o5’gjdodeca-6,11-

diene 87.

91

91

91

93
93
93

9A

9A

Chapter Page

Temperature Effect on the Formation of
Compound 87 . . . . . . . . . . . . . . . . . . 95

Preparation of 1-Chloro-3-(dihydro-

indene)-l-Propene léz . . . . . . . . . . . . . 96
Attempts to Prepare 3-Chlorocyclopropene. . . . 98
A. Using Sodium Amide. . . . . . . . . . . 98
B. Using Potassium t-Butoxide. . . . . . . 98

REFERENCES. . . . . . . . . . . . . . . . . . . . . 102

Figure

LIST OF FIGURES

Isomerization mechanism for the

photolysis of cis,syn,cis-tricyclo—

 

[8.2.0.02’9]dodeca-3,5,7,ll-tetraene
(it)

New (CH)l2 hydrocarbons synthesized
from tetracyclo [5.3.2.02’5.06’8]-
dodeca-3,9,11-triene.

Thermally allowed (W28 + "2s + n25)
interconversions.

Preparation of Tosylhydrazone (6%).
250 MHz proton nmr spectra of diene
(it)-

Proton decoupled 13C nmr spectra of
diene (58).

Proton coupled l3C nmr spectra of
diene (58).

Cyclopropone containing symmetric
structures possible for diene (58).
Decoupled proton nmr spectra of diene
58. Irradiation at (a) 6.05, (b)
5-“5, (c) 3.35, (d) 3.15, (e) 2.9,
(f) 1.91, (g) 1.75 ppm-

Page

12

22

25

26

27

28

3O

Figure Page

10 Proton Chemical shift and coupling
constant assignments in diene 88. . . . . . 31
ll Clefinic chemical shifts (ppm) for

bicycleEn.2.1] and [n.2.2] systems. . . . . 33
12 Proposed procedure for preparation

of deuterated tosylhydrazone salt

“fig-q. o o o o o o o o o o o o o o o o o o 0 [I2
13 A plausible mechanism for the
formation of diene 88 . . . . . . . . . . . A3
19 250 MHz proton nmr spectra of
compound 86 . . . . . . . . . . . . . . . . 45
’L’b
l5 Proton chemical shift and coupling

constant assignments in 88 (top),

and reported assignment in 81

(bottom). . . . . . . . . . . . . . . . . . A7
16 A plausible mechanism for the

formation of compound 88. . . . . . . . . . U9
l7 Rearrangement of some [6.1.0] deri-

vatives to the dihydroindene and
[A.2.l] systems . . . . . . . . . . . . . . 57
18 Mechanism for the formation of

diene 88 and pyrazole 88 from

the pyrolysis of salt 2%. . . . . . . . . . 62
19 Pyrolysis apparatus for decomposi-

tion of dry salt 88 . . . . . . . . . . . . 80

ure Page

H

0‘)

20 Pyrolysis apparatus for isomerization
a c: 6‘
01 compound 8%. . . . . . . . . . . . . . . 8o
21 Proton nmr spectra of pyrazole 88 . . . . . 99
22 Proton nmr spectra of pyrazole 88 . . . . . 100
23 Proton nmr spectra of tosylhydrazone

88. . . . . . . . . . . . . . . . . . . . . lOl

INTRODUCTION

The chemistry Of (CH)n hydrocarbons has been studied
intensively over the past two decades. The reasons for
this are many but include the discovery of bullvalene by
Schrader in 19631 and the chemist's surprise and joy at
the range of isomers related in both an energetic and con-
ceptual sense. The behavior of the (CI—i)lo hydrocarbons
has been mimicked by the other (CH)n's, and the entire
area has become a fertile ground for the discovery of new
compounds and reactions. As a result, many of the pos-
sible (CH)82 and (CH)103 structures have been synthesized
and much is known about the diverse and surprising rear-
rangements which occur thermally and photochemically. The
early review by BalabanLl which published a series of com-

puter generated valence isomers of (CH) hydrocarbons

n
(where n = 2,3,11,5,LIa and n = 6ub) has been very useful and
remains the excellent compendium of (CH)n isomers.

The isomeric (CH)12 hydrocarbons present an interest-
ing family of compounds because of the members, and the
varied electrocyclic and sigmatropic processes expected
of the numerous valence tautomers. Despite these attrac-

tive features, chemical investigation in this area has

been limited because of the relative unavailability of

synthetic entries to these polyenes. For these reasons,
various research groups have been interested in the pos-
sibility of developing facile and stereochemically con-
trolled syntheses of several (CH)12's. Some of the find-
ings for (CH)12 hydrocarbons are mentioned below.

Schr5der has synthesized tWO (CH) hydrocarbons % and

8m

12
by pyrolyzing the Diels-Alder adducts of the dimers of

cyclooctatetraene and dimethyl acetylenedicarboxylate

(DMAD) 8 and 35’6 (Equations 1,2).

I awash

’b

 

 

 

PUT

[3

L3

 

 

8F!

Low temperature photolysis of hydrocarbon % resulted in

the formation of several other (CR)19 hydrocarbons7

 

 

 

 

 

 

 

(“Dino
..., \ V _/ 2
m
._...J / ,___J
1302MB
6 A
'b 'b
A (2)
V
V
I j
7:

(Equation 3).

' 3”“

1 ”ML-30° 1 Q. 2
(CH =Cle-CH =CH2 ‘

+ O

2)0t 2 °
° ° (3)

The formation of hydrocarbons I and 8 was found to have
arisen through the unstable [l2] annulene 88.8 This [12]

annulene could then rearrange thermally or photochemically
into Z or 8 in accordance with the Woodward-Hoffmann rules.8
It was also proved that 2 and 8% were formed thermally at
the expense of Z while 88 could result from a photochemi-

cally induced suprafacial sigmatropic 1, 7 [H] shift in Z

).

hD- ° 0
1 $ b”, >-
"J 4
tux-100°
l2
'Vb

r4

8 .
and/or 8 (Figure

 

 

 

8
m
A .-4o° "Dr-100°
A:
—-.A 3 / >3o°
+20 \ ' h), 5
7
.. 2 a
1JHH§
8
Z or m h” _____€’ $2
. H J
ti '
Figure l. Isomerization mechanism for the photolysis of gig,

syn, cis-tricyc1o[8.2.0.02,9]dodeca-3,5,7,ll-

tetraene l.
’b

U)
C
H
(.1.
(D
Q

On the other hand, heating of compound % at 120° re
in the formation of equal amounts of exo-tetraene l3 and

o
benzene5H (Equation U)

- —>m° tho

1: U3. H

 

 

L

Two possible mechanisms have been suggested for the selec—
tivity of this reaction to the formation of exo-isomer lg.

First, a suprafacial [1,5] sigmatropic shift, and second,

a Cope rearrangementgb’lo (Equation 5)

M x .
W 1.5“” $609. \ /. (5)

#3. %

 

%

Deuterium labeling experiments ruled out the Cope rear-

rangement path in favor of the [1,5] sigmatropic shift.ll

Irradiation of hydrocarbon %5 under triplet condi-
tions (acetone, ET = %82 Kcal/mol) afforded hydrocarbon

39b (Equation 6).

‘VV
hD a
O acetone I 1 (6)

 

 

The formation of compound g was explained according to the

Katz-Cheung mechanismBk'9b (Equation 7).

Q (7)

 

 

 

On the other hand, direct photoisomerization of hydro-
carbon $£ resulted in two other new (CI-{)12 members, formed

in equal amount9b (Equation 8).

16
mm

'V'b

In 197M, Daub completed the set of tetracycloEu.U.2.O2’5.-

O7’lojdodecatrienes, (lg) - (lQ) by synthesizing the

. 12
endo, endo isomer lg.

 

 

He showed that %Q on sensitized irradiation went to the

known cage compound lgl2 (Equation 9).

1

NW N2

 

Pyrolysis of hydrocarbon % in the gas phase at 1:800 af-

forded the new (CH)12 isomer £913 (Equation 10).

v I] 480°a £9 (10)

20

NW

 

 

RM

The conversion of g to a hydrocarbon g3 was formulated as

follows13 (Equation 11).

 

é ’ a

Several other new (CH) isomers have been prepared

12
through a multi-step direct bond reorganization of hydro-

carbon £30,1u

(Figure 2). Conversion of 2% to 2“ is an
’L "V‘b
example of the well precedented15 (02a + 02a) bond re-
location process which simultaneously converts a set of
four multiply fused cyclobutane rings to two pairs of
cyclOpropane and cyclopentane rings. It was thought
that diene 3% might serve as an immediate precursor to

the desired tetraene 31.14

Thus thermally activated 3%
could experience symmetry-allowed intramolecular [nus +
"23] cycloaddition with utilization of one internal cyclo-
propane bondlLl to provide QR (Equation 12). The strained
nature of this polycyclic hydrocarbon was viewed as ade-
quate to allow subsequent homolysis of the indicated triad

of cyclopropyl bonds, perhaps via free radical inter-

mediates, to deliver £1.1u
Pyrolysis of diene éé up to 580° did not eventuate

in recognizable isomerization to 31 as desired},4
In 1975, Farnum reported a new (CH)12 isomer %l which

was prepared through a multistep reaction sequence from

 

 

2
ML
poms/no
v .
—-“’ \e-
g a
Dogma. ‘
r
pontam in” sentencing

 

-65 am
a W”-

lcuono n» W
acetone no . «24¢

i

6' £6 <1 fi'u/

 

1
mg g; 3%

Figure 2. New (C H)l 2hydro carbgm synthesized from tetra
cyclo DES 3. 22 02 5 OO ]dodeca- ,9, ll- trie ne 2.

lO

 

----> ---->
(12)
27
£2 £2 «A,
compound $2 as starting material16 (Equation 13).
(0
no -> -’ .9 -> +

 

This hydrocarbon has the potential to undergo a series of

structurally degenerate Cope rearrangements, one of which

is illustrated below (Equation 14).

 

11

The complete cycle leads to the scrambling pattern in 31:

eight positions (marked 0 ) form one equivalent set, while

16

As shown, each

16

the remaining four comprise another.
Cope rearrangement also interchanges enantiomers. Initial
work (up to 140°) showed that the Cope rearrangement, if
present, is slow on the nmr time scale. This slow rate,
even though the geometry appears ideal, was conjectured
to be due to the absence of a small ring and its accompany-

ing strain.lo

Truncated Tetrahedrane

 

The (CH)l2 isomer éé is of interest as a potential
photochemical precursor of the hydrocarbon heptacyclo-

[5.5.0.02’12.03,5,0“,10,06,8.O9,11

jdodecane 3%, otherwise
called "truncated tetrahedrane", because of its tetra-

l7

hedral symmetry. Compound §U, although as yet unknown,

"4

is of much theoretical interest, owing to its cage-like
array of cyclopropane rings. The quadruple tris-homo-
benzene nature of 3% makes it and its valence tautomer %%
an ideal system for testing the theory of homoaromaticity
in neutral molecules. Since at one time any three of the
cyclopropane rings could be involved in this process, there
would be four identical tautomers possible for éé. This

is illustrated in Figure 3. Whether the delocalization

energy of compound $3 would balance strain energy and pre-

vent its decomposition to @§ is difficult to predict. A

12

$

2,238. «3%

y

«621/
fia‘R

r)

A

Figure 3. Thermally allowed (W2 + n“ + n2
conversions. 28 ‘8 8

$38

) inter-

lesser stability of %5 might still permit its detection as
an intermediate in the degenerate interconversion of ééa,
b, g and d. This could be done by a study of the variable
temperature nmr spectrum of éé, and hence the relative
energy of 3% can be estimated. On the other hand, the

homoconjugative interaction in Q; can be determined by

l3

finding the ionization potentials of the interacting double
bonds18 and comparing these with the ionization potentials
of isolated, noninteracting systems. There are some ex-
amples in the literature which show the application of
photoelectron spectroscopy as a tool for determination of

homoconjugative interactions in molecules with three prOperly

disposed double bonds, such as compounds %§,19 and éé.2o

 

32 ' w

The photoelectron spectrum of compound 3% has shown a
large through space interaction of the n levels and a

small through bond interaction.19 The photoelectron spec-

Okl

trum of éé suggested a much smaller overall interaction
of n levels in 3% relative to compound éé.20 On the
other hand, there is some evidence for homoconjugative
stabilization between two adjacent cyclopropane rings in

diademane @1, although this stabilization is less than

18e

expected. The observed destabilization was explained

as the inductive effect of the central sp3 carbon atom,

Q
which ties the cyclopropane ring together.lve Compound éz,
on heating to 90° underwent the orbital symmetry allowed

. 2 . . L . .
[023 + 025 + 02$]cycloreverSion, l aifording triquinacene

lu

éé. This reaction showed the considerable amount of ring

strain, which is present in compound $1.21

The existence
of an extra cyclopropane ring in compound éé might result
in a geometric arrangement of n bonds similar to that of

cyclononatriene 3%. On this basis, some homoconjugative

stabilization in compound @% would be predictable.

Synthetic Approach to Truncated Tetrahedraneiéfi

Vedejs has reported an elegant synthesis of pentacyclo-

2 12.06,8

[5.5.0.0 " .03’9Jdodeca-U,ll-diene @2 using the diazo

compound §§.22

A possible approach to 5%, as a potential photochemical
precursor of truncated tetrahedrane @Q involved the Cope

rearrangement of a divinylcycloprOpane 30 which in turn

15

22a

was expected to be available' by retro Dials-Alder

cleavage of %2 (Equation l5).

0
V A v ”‘3
A “7-9’

v
i2 gag

(15)

 

Thermolysis of $2 above 160° gave benzene, and not hydro-

9
carbon %0.2“a The formation of benzene from compound £2
was explained22b according to the following mechanism

(Equation 16). The most direct, simple and elegant pro-

posal investigated for the synthesis of %% depended on

the addition of two acetylenes to cyclooctatetraene in two

‘-J
C“

(16)

 

 

 

NW ’D
L 7‘r‘rrgf‘7 *109-rxnkgfl“? nag. [7T .1. TT + Tr + 7T ]
serT‘Lee/rv] a;—I—J‘l‘lv‘d pl. V'vu..\4&.A-‘v .L. 23 ‘ 2S 2S 23
Q -I—-
l" ‘ I
reactiorf3 (Equation i

#3 NH

’V‘b ’Vb

(17)

17

This reaction has been tried under a variety of conditions
23

23

involving different solvents, temperature, and time.
The only photolysis that yielded an insolable adduct
was the one in which dimethylacetylenedicarboxylate (DMAD)

and cyclooctatetraene in methylene chloride were photolyzed

in the presence of benzophenone as a sensitizer at -60°

(Equation 18).

2°”3

CO»
.—.——> °°’°".3

ti ~ t2

23

A plausible mechanism for the formation of Q5 was explained

as follows (Equation 19).

. L9) omnm,
§\::ff:2 2+2

a £33.

 

 

 

-C02CH3

cozca3

 

 

l8

'1 0 2 '
A somewhat less direct proposed method 3 for the syntheSis
“ 0'9 ' 9“ ”W ' -T‘R .'
Ol éé, was the Den.ration Oi the (ch,12 isome- m%’ This
compound was expected to be prepared from hydrocarbon 2%,

which in turn could be generated from decomposition of

tosylhydrazone salt 3323 (Equation 20).

— NTs 0'

£53

4] ex— 0’ {l (20)

a a

Tosylhydrazone salt :3 was prepared, and its photolysi in

[\J

'

c Q Q ‘ 0
dry tetranydrofuran, led to tne new (Ch)l2 isomer él.

s
3

Attempts to produce Q2 fr m 51, both photochemically and
’L U’L '

   

-— O
' 270 9 I + / 4.
tetraglyme
39 23 55 it

On the other hand, thermal decomposition of the dry tosyl=

hydrazone lithium salt 5% at 250° led to the formation of

the two Lnown epim

ric tetraenes 1% and 22, and a new

x“, e

22

 

Q1 7&3. 3?. 3°.

According t0 the spectroscopic data and using Balaban's

1'.
LV‘.
:0v 1 — \ L: ' a .‘ ‘ V 9" “W ‘ "Y’
plana° tr -a~er. mul.-graon 3; order i2, the st.u -i-e

2O

. . . ll
of §% was aSSigned to this new isomer. Unfortunately,

the spectroscopic information did not allow rigorous assign-

ment of the structure of this new (CH)

12 member as §§.

The original purpose ofthngnTUect was to reinvesti-

gate the

order to

(a)

(b)

(C)

(d)

We were

tion of

expected

pyrolysis of tosylhydrazone lithium salt 2% in

permit:

careful analysis of the product mixture to find

out any other known or unknown (CH) isomers,

12
Generation of this new isomer, and studying its
spectrosopic data to find out the exact struc-

tu

*3

8’
Mechanistic investigation of the formation of
E
hydrocarbons l3, %% and <§,
Development of another method for the production
of diene 58 with higher yield (because under the

mentioned conditions, it was isolated in 1.0%

yield).

also interested in studying the thermal isomeriza-

cyclopropene hydrocarbon §%' Hydrocarbon él was

to be a potential precursor for the pyrolytic

formation of diene 5Q.

RESULTS AND DISCUSSION

Part A

Synthesis of Trans—8-[anti—9-bicyclo[6.l.O]nona-2LU,6-

trienleacrolein Tosylhydrazone éé

 

The general procedure for the synthesis of a large

23

quantity of tosylhydrazone éé was adapted from S. Raghu

811

and T. Reitz' theses. This is illustrated in Figure H.

Thermal Decomposition of Trans-B-[anti-9-bicyclo[6.l.OJnona-

 

2,4,6-trienleAcrolein Tosylhydrazone Lithium Saltgéz.
Preparation of Exo-tricyclo[u.u.0.02’5]dodeca-3,7,9,ll-
tetraene kfi, Endo-tricycloEM.“.O.O2’5]dodeca 3,239,11-

2’12.O3’7.Ou’lleodeca-SL9-

tetraenegg, Pentacyclo[6.B.0.0
diene QQ, 1,2-Benzocycloocta-l,3,7-triene,ég, 9 syn and

Anti(5-pyrazola)bicyclo[U.2.l]nona-2,H,7-trieneg3, éé

The best method that we found to pyrolyze the tosyl-
hydrazone lithium salt QT was to add it in small portions
to a hot flask maintained at 250° in a sand bath. After

each addition, about 10-15 glass beads were added to pro-
vide a fresh surface for the pyrolysis of salt. The vola-

tiles were then pumped into a trap kept in liquid

21

22

 

 

CHNzCOZEta > COZCHZCH3
CUSO4 “H
”3 59
’L’b NW
UAIH4
\J/
(3
H
. C‘H<(Cr03-Py) > CHZOH
“H CH2C'2 “H
61 60
’\.a’\: ’b’b
H

I l
1)(Et0)2PCH =CH-N—06H" . NaH

2m *
3o

 

   

Figure U. Preparation of Tosylhydrazone éé.

23

nitrogen. There were some less volatile products which
were deposited on the extension tube wall between the flask
and trap. GC/MS analysis of the volatiles showed the pres-
ence of five products. Mass spectra taken showed all these
compounds to have molecular ion peaks at 156 corresponding
to (CI-i)l2 hydrocarbons. gas chromatographic separation

of this mixture gave four major products éé: 1%, éé and éfi
in a ratio of u.0:2.2:2.0:l.0, respectively (one of the
compounds was not enough to be identified). On the other

hand, by flash chromatography of the less volatiles, two

pyrazoles §3 and 5% were obtained in a ratio of 2.7:l.O,

respectively (Equation 23).

 

Compounds l5, gg and £3 were identified by comparison

of their proton nmr chemical shifts with the literature

values.9b’lu’2u

2“

PentacyploE6.“.0.02’12.03’7.0u’lljdodeca-5,9-diene5%

The mass spectrum of diene 5% showed a molecular ion

peak at 156 corresponding to ClZHl2 hydrocarbons. The

250 MHz proton nmr (5, CDC13) (Figure “) showed peaks at:
1.75 (dt,J=“.7 and 7.0 Hz, 1H), 1.91 (ddt, J=7.0, 5.5 and
1.5 HZ, 2H), 2.90 (m,2H), 3.15 (ddd, J=9.3, 5.5 and 1.5 Hz,
2H), 3.35 (dt, J=“.7 and 5.5 Hz, 1H), 5.u5 (t, J=l.2 Hz,
2H), and 6.05 (dd, J=5.8 and 2.8 Hz, 2H). The proton de-

coupled 13

C nmr (6, CD013) (Figure 5) showed lines at:
l3“.8 (2c), 131.3 (20), 66.3 (1c), 62.6 (2c), “1.8 (2c),
36.1 (2c), and 26.6 (1c). The proton coupled 13C nmr (5,

CDC13) (Figure 6) consisted of peaks at: l3“.6 (d, J=160.9
Hz, 2c), 131.1 (d, J=156.“ Hz, 2c), 66.2 (d, J=137.8 Hz,
1c), 62.3 (d, J=l37.8 Hz, 2c), “1.6 (d, J=l35.9 Hz, 2c),
36.0 (d, J=l66.5 Hz, 2c), and 26.“ (d, J=l71.1 Hz, lo).

13

According to the proton decoupled C nmr, the molecule has

a plane of symmetry reflecting five pairs of carbons and

containing the two others. On the basis of the proton
coupled l3C nmr, the three carbons located at 36.0 and

26.“ ppm with C-H coupling of 166.5 and 171.1 Hz belong to

25

a three membered ring. With these data in hand and

Balaban's graph,“b

the structure of the diene can be one

of the possibilities, 2-1-2-5, 2-1-2-9, 2-1-0-3, and 2-1-2-1
(named using Balaban's nomenclature, B: t, g, S; where

B is the number of double bonds, t is the number of three

membered rings, g is the number of four membered rings

25

.WW ocofip uo mpuooom LE: COQOLQ N12 0mm

anbehhbbpbb

 

 

.a ..
bbfbb-pbhbfi

4
bib-blpbbh b-hb-Pbp

.0

4
bbhkppppppb pup-....b

 

 

11 1

 

_

.m ohzwflk

OM 9H
bub-b-hhh hub-nhbbb nbbbh

 

W

 

 

.Ww ocmflp Lo mgpooom LE: Qmfi U®HQ30oop couogm .w ohzwflm

..4.~441._aa4._..s.4.....a

I!» A .

 

viii-Iv» I “bit-III Lb Fr
(1‘1qu .d .1114! 111a .5114- ! {udnn 1-‘ ‘

 

 

27

.WW ocowo mo oppoodm LE: omH ooHQ300 couopd .m mpzmfim

.- 3 a 3. a: 3.
111—11-dddiddquqdq<11d‘114dddqd

c.-ddqdddd1_ddqd1<ddqd<<ddfldid‘dqdfidqdddd

:-
411

28

ole >

 

 

2- - -
1 2 5 2-1-1-11 2-1-2-9
“|||i||!I'i? ZC::‘||lli;>
2-1-2-1 2-1-0-3
Figure 8. Cyclopropane containing symmetric structures pos-

sible for diene 58.

and S is a serial number) (Figure 8)?b Since the ultra-
violet spectrum of 58 showed no absorption above 250

nm11 and since proton nmr decoupling experiments (see the
spin decoupling results) showed the olefinic protons were
not coupled to each other, we can say that the diene 58 is
not a conjugated diene26 and that the plane of symmetry

must bisect each double bond. These two criteria eliminate

the 2-1-2-5, 2-1-1-11, and 2—1-2-1. Isomer 2-1-2-9 cannot

29

be the diene 58, because the two olefinic pairs should be
coupled with the same bridgehead protons. As a matter of
fact, the spin decoupling studies showed that the olefinic
pairs in diene 58 were coupled with different bridgehead
protons. These considerations, and also the direct genera-
tion of diene 58 from decomposition of lithium and sodium
salts of tosylhydrazone 65 both thermally and photochem-
ically (see next parts) convinced us that the structure

of diene 58 was that of 2-1-0-3.

1'
_NNTS

65
’Vb

Proton chemical shift and coupling constant assignments in

diene 58 were made on the basis of spin-decoupling experi-

ments. The results are illustrated in Figures 9 and 10.
The multiplet signal at 2.90 ppm (2H) was coupled to sig-
nals at 6.05 (2H), 3.15 (2H), and 1.91 ppm (2H). Thus,

this was assigned to the bridgehead protons H which

8,11

are adjacent to the olefinic protons H9 10’ the bridgehead
2

protons H“ and the two bridggprotonsHl 19. This
, i

,7’
assignment was confirmed since the signal at 3.15 ppm

(2H) was coupled to the signals at 5.“5 (2H), 3.35 (1H),

3O

 

 

.11 11.1.

J)
I
I
I

 

 

. . A“ II

t _.J w”; “—e ”WV;—

 

9 “—2; \JLJJJ \J' ‘J‘Lfi u

Figure 9. Decoupled proton nmr spectra of diene 58. Ir-
radiation at (a) 6.05, (b) 5.“5, (c) 3.35, (d)
3.15, (e) 2.9, (f) 1.91, and (g) 1.75 ppm.

31

 

mw ocoap Ca mucoscmfimmm ucmpmcoo wcfiadzoo new pufizm HmoHEozo coaomm

.oH mtzwfia
Lin
Q..-
”.°H-~V\u \l' .....I In."
/_ \\ é
_
m .
A)“. . numv.nv
7.2.83... .
_
.
.
.
.
. .
39.3 _
_

32

and 2.9 ppm (2H). As a result, the signal at 3.15 ppm was

assigned to the bridgehead protons H“ 7 which are vicinally
3

 

related to the olefinic protons H5,6’ the single bridge
proton H3, and the bridgehead protons H8 and H11.

The assignment for olefinic protons of diene 58 is
in agreement with some similar reported compounds in the
literature. Two olefinic protons H5 and H6 belong to a
[“.2.1] bicyclic system, while the other two H9 and H10
are located in a [“.2.2] bicyclic system. Figure 11 lists

the reported olefinic chemical shifts for several similar

bicyclic compounds.

9-syn and anti (5-pyrazola)bicyclo[“.2.1]nona-2,“,7-trienes
zit—jam 2

The mass spectrum of pyrazole 5“, the major product,
showed a molecular ion peak at 18“. The 60 MHz proton
nmr spectrum (6,CDCl3) showed peaks at: 3.1-3.“ (m,3H),
5.12 (s,2H), 5.8 (bs,5H), 7.1 (m,lH), and 11.0 (bs,lH).

l3

Proton decoupled C nmr (5,CDC13) consisted of peaks at:
135.““ (2C), 126.09 (20), 122.87 (2C), “6.37 (2C), and
36.07 (10). The spectrum also included three small peaks
at l“5.69, 13“.“8, and 10“.20 ppm belonging to the pyrazole
ring.31

The molecular ion peak of pyrazole 55 similarly ap-

peared at 18“. The 60 MHz proton nmr spectrum (5,CDCl3)

33

“SC. ’ 1.41%

Ref. 27

Ref.28 .
H
6.1 DC
H

Ref. 30

Figure 11. Olefinic chemical shi-ts (ppm) for bicyclo~
[n. .1] and [n.2.2] systems.

showed peaks at: 2.95 (s,lH), 3.12 (d,J

6.0 Hz,2H), 5.08

H). Proton de-

f\)

(s,2H), 5.6-6.1 (m,5H), and 6.98—7.1 (m,
13

coupled C nmr (6,CDC13) consisted of peaks at: 135.75
(28), 12“.26 2C), 121.21 (2C), 50.08 (2C), and “0.22 (1C).

A ° A o“, ‘ R . . v r1 "a: ‘— ..
Because 01 ; neisy baseline, it was not pOssible to dis-

3“

The stereochemistry of pyrazoles 55 and 55 were assign—

ed unambiguously upon comparison of their nmr spectra with

that of bicycloE“.2.l]nona-2,“,7-triene 5532 and its 9-
substituted derivatives.33
H H
Sm H CN N H
anti C syn H . OCH3
an:
66
m, 21 £2 éfé
In compound 66, the dihedral angle of H and bridgehead
mm syn t

protons is 90° while the dihedral angle of Hanti with the

bridgehead protons is close to 0°.33 Hence, the nmr of Hsyn’

split only by H appears as a doublet, whereas that of

anti’

Hanti’ split by HSyn

as a triplet of doublets.33 In case of compounds £13“

and bridgehead protons H1 6’ occurs
3

and 5533, the peaks belonging to H appeared as a triplet

anti
at 3.13 ppm (J=6.0 Hz) and 3.85 ppm (J=6.2 Hz), respec-

tively. On the other hand, the HS in compound 553“ ap-

3“

yn
peared as a singlet at 3.50 ppm. 80, the appearance of
a multiplet at 3.1-3.“ ppm in the spectrum of pyrazole 55
should be an overlap of peaks belonging to the bridge and
bridgehead protons characteristic of syn epim r, while the

appearance of a singlet at 2.95 ppm in the spectrum of

pyrazole 55 characterizes the anti-epimer.

35

Mechanistic Investigation of the Tosylhydrazone Lithium Salt

51 Decomposition

 

As is known, decomposition of the tosylhydrazone salts
of aldehyde and ketones both thermally and photochemically
35

leads to the formation of carbenes. However, in the case
of tosylhydrazone salts of a,B-unsaturated aldehydes and
ketones, the amount of carbene and its subsequent reactions
strongly depends on the number of substituents at the

36

8-position. Thermal decomposition of the sodium salt
of a, B-dimethylcrotonaldehyde tosylhydrazone 15 has been
reported to give trimethylcyclopropene 11 in 72% yield36b
(Equation 2“). The presence of one hydrogen at the 5—

position diminished the yield of cyclopropene Z3 substan-

tially to “% and led to the formation of 3,“-dimethy1

pyrazole Z5 in 60% yield36b (Equation 25).
‘CH ‘ CH3'
cUHs
/—\__ ? NaOC (2“)
CH3 __ N ms 150°
CH3

(.4;
(2H: 9H3 3 / \
+
NaOCH3> N (25)
‘/F—_—_fi\\____ 7 o CPI N/’
H CH3

1% Z3 15

On the other hand, no cyclopropene has been observed from
the decomposition of tosylhydrazone salts having two

.5 36b f.
hydrogens at the 8-pOSition. Formation o- pyrazole

could result from cyclization of the diazo intermediate

and subsequent [1,51 hydride shiftj6 (Equation 26).

Q 1.5[I-I]E If},
V” H

(26)

@369?

It is clear that the hydrocarbons, 55, 52, 55, and 5% have

R ”a
//
6

Rib-l

arisen through the carbene intermediate while the pyrazoles
5% and 55 were formed either through the cyclization of
salt or diazo intermediate and subsequent [1,5] hydride

shift.

(.

51’s
6

//‘
K

37

A Look at the Plausible Mechanisms for the Formation of

Tetraenes 1“ and 22
’b NW

A

—7U

Paquette has reported that pyrolysis of cis, syn, cis-
tricyclo[8.2.0.02’91dodeca-3,5,7,ll-tetraene 5 at 120°

afforded the exo-tetraene 58 (Equation 27).9

\/

 

— I—w-T 120° 0 - (27)

 

 

 

’b’b

It seems likely that the anti-isomer Z5 would isomerize

 

to endo-tetraene 88 in an analogous fashion (Equation 28).

 

T > (28)

 

 

1% 3%

Formation of primary products 5 and 15 from carbene 58 may
have arisen according to the following mechanism (Scheme 1).
The bisected cyclopropyl carbonium ion 15, the mesomeric

structure of carbene [8, is in conformational equilibrium

with the bisected cyclopropyl carbonium ion 58. Although

38

 

 

 

 

 

0

3&3, ’ %%

Scheme 1. A plausible mechanism for the formation of

1a 99 . v”
tetraenes cm and fit from carbene (8-

the conformer (1 seems favored over conformer 1? because of
its transoid arrangement, the intermediate QR would be

favored over £2 because the double bond is anti to the

 

eight membered ring. The stereoselectivity of the reac-

tion toward the formation of the endo-tetraene 22 as the

 

major product requires that if the reaction goes through
this mechanism, the pathway B would be favored over pathway

A.

On the other hand, the carbene intermediate Kg could have
generated the diradical intermediate Q; which upon subse-
quent cyclization could lead to tetraenes %% and 22 (Equa-

tion 29).9

 

 

(29)

H,

An important experiment which can distinguish between

these mechanisms, would be the thermal decomposition of

MO

tosylhydrazone salt 51 with deuterium at the B-position
(Scheme 2). The formation of tetraenes through Scheme 1

would result in compounds l3 and 2% with deuterium on ali-

’U

hatic carbons, while intermediate Q% will end up with
scrambling of deuterium at both aliphatic and olefinic car-
bons. Deuterated tosylhydrazone salt gz-d could easily be
prepared as follows (Figure 12). Unfortunately, this ex-
periment has not been performed, but work is currently in

progress.

A Close Look at the Mechanism to Hydrocarbons §§L_§fl and

Pyrazoles éngéfi

 

 

A straightforward mechanistic pathway leading to
diene EQ might be through the intramolecular Diels-Alder
addition of compound §2, which could have been formed
from a suprafacial [1,5] sigmatropic shift of cyclopropene
él (Figure 13). To test this, we decided to look at the

pyrolysis of cyclopropene @l.

Thermolysis of anti-9-(A2-cyclopropeno)-bicyclo[6.l.O]-
nona-2,u,6-triene_§l. Preparation of Pentacyclofl6.D.O.-

02’“.03’10.05’9Jdodeca-6,ll-diene Q

80x

Many attempts at pyrolysis of cyclopropene 3%23 using
different methods either gave the starting material or

polymers. We found that the best method for pyrolysis

 

D 22-d
mmmm
Scheme 2.

41

 

 

 

' ' n
9 __,+
33:2.
iaé Z§tQ

(Vital, éété

Thermal decomposition of deuterated tosyl-
hydrazone salt glad.

 

If]?

 

U2

CHNgCQgEt; b c02cr12cu3
Cuso4 ~.H

3,3. 22

 

 

" P-TsNHNHg;

HOAc

 

Figure 12. Proposed procedure for preparation of Deuterated
Tosylhydrazone Salt éz-d.

43

 

 

Figure 13. A plausible mechanism for the formation of
diene SQ.

'Hu

0

01 hydrocarbon él was to add its solution in tetrahydro-
furan to a hot flask connected to a hot column containing
glass beads, both at 300° under an argon stream. The vola—
tiles were pumped and collected in a trap kept in liquid

nitrogen. Gas chromatographic separation gave hydrocarbon

Qé, a new (CH),2 member, in 2.6% yield (Equation 30).
I ‘s
7

 

/ (30)
2,1 9?,
Hydrocarbon éé was identified as pentacyclo[6.U.O.02’u.-

1 _ Q -
03’13.09”]dodeca-6,ll—diene (Balaban's number, 2-l-O-2)Lb

because of the closely parallel of its proton nmr spectrum

to that of the known compound éz.37

Cl
Cl C!

$1

The mass spectrum of hydrocarbon showed the molecular

86
WW
ion peak of 156. The 250 MHZ proton nmr spectrum (6,CDC13)
(Figure lb) of compound fig consisted of peaks at: 0.75-
0.90 (m,2H), 1.75 (ddd,J=7.9, 4.9 and u.1 Hz,lH), 1.85

(dd,J=6.2 and 3.3 H:,lH), 2.35 (ddd,J=7.5, 6.2, and 5.1 Hz,

145

.ww pcsoquo mo oppooam LE: couOLQ Nu: 0mm .:H ogswflh

1*1‘441414+J‘1‘4‘4ld‘111‘1‘1111A1‘411¢“1d‘1‘1(“11q 444444444 q*‘11£

3.36..

 

 

 

 

U6

1H), 2.38 (dd,J=7.9 and 6.2 HZ, 1H), 2.82 (dd,J=5.l and
3.2 HZ,lH), 3.06 (dd,J=7.5 and 5.8,1H), 5.55 (dd,J=5.0 and
3.3 Hz,lH), 6.12 (dd,J=S.O and 3.3 HZ,lH), 6.33 (dd,J=7.9
and 5.8 Hz,lH), and 6.55 (dd,J=7.9 and 6.2 Hz,lH).

Proton chemical shift and coupling constant assignments
in compound @6 were made in the same way as that of the

37

similar structure 61. Figure 15 shows the chemical
shift and coupling constant assignments in compound 66 and
the reported assignments for compound 67.37 Because of its
similarity to compound 61,37 the proton chemical shift
assignment for compound 66 was straightforward except for
the cyclopropane hydrogens. Indeed, the three cyclopropane
protons appeared at 1.75 and O.75-O.9 ppm as a doublet of
doublet of doublets and a multiplet in a ratio of 1:2. A
molecular model showed that, of the three cyclopropane ring

protons, H3 and HM have dihedral angles near 90° with their

respective vicinal protons, and H5, while H2 had a di-

H10
hedral angle with the bridgehead proton H1 near 0°. As a

consequence, the single proton at 1.75 ppm was assigned to
H2 which showed a large vicinal coupling of 7.9 Hz to the
bridgehead proton H1. The difference in chemical shift

could arise from the diamagnetic anisotropy effect of the

double bond C —C

8 ll 12 which is experienced d1f.erently by H2
‘2

and H ,
3,“
The formation of hgdrocarbon 86 can be explained accord-

ing to the mechanism proposed by Mock for the formation

“7

 

 

 

 

 

12.1 K H /
J \\ 4 £5.87) I,
)o ‘x \ \ I I -
0 200 V \ V/ J7,6‘5'9

Figure 15. Proton chemical shift and coupling constant
assignments in 86 (top), and reported assign-
’\:
ment in compound éz (bottom).

U8

".7
of the similar compound 81 as follows3‘ (Figure 16). The

intermediates 88 and 8% may be produced by disrotatory ring
closure of initial product 52.37 From these two, only 8%
can feasibly undergo an internal cycloaddition to give 86.37

Incidently, the retention time for compound 86 was

exactly the same as that of the unidentified minor compound
rom the pyrolysis of salt 57. If this compound is 86,

one can definitely say that it could have come from cyclo-
prOpene hydrocarbon 51. This in turn means that the cyclo-
propene hydrocarbon 5% has been generated from the pyrolysis
of salt 5x, but rearranged to 86 under the pyrolytic condi-
tions.

As we discussed, cyclopropene 5% cannot be the pre-
cursor for the formation of polycyclic 58. Other pos-
sibilities for the formation of hydrocarbons 58, 65 and
pyrazoles 5% and 55 are shown in Scheme 3. The formation
of epimeric pyrazoles 55 and 55 could have come from, (1)
cyclization of diazointermediates 2% and 22 (path F) which

were formed either by a step-wise [1,5] shift of diazo

intermediate 26 (path 8) or from the two syn and anti

 

tosylhydrazone salts 2% and 23 (path D) which were gen-
erated from a step-wise [1,5] shift of salt 51 (path C),
or (2) a step—wise [1,5] shift of pyrazole 25 (path B).
All these pathways seem possible for the formation of
pyrazoles 5% and 55. The two hydrocarbons 58 and 6%

could have come from the carbenes 26 and 2% which may

“9

 

 

 

 

Figure 16. A plausible mechanism for the formation of
compound 86.

50

 

 

 

Scheme 3. Thermal decomposition of tosylhydrazone salt
57.
mm

51

have been formed either from a step-wise [1,5] shift of
carbene [é (path H) or from the diazo intermediates 2% and
52 (path G). From these two (path H and path G), the first
path which requires a [1,5] shift ofashort-livedspeciessuch
as vinyl carbene 76 through a step-wise process seems less
likely. As a consequence, carbenes $6 and 27 as the pre-
cursors for the formation of hydrocarbons 58 and 65 (and
probably tetraenes 1A ar d 22) were formed from the re-
arranged tosylhydrazone salts 2% and 2%. Although we did
not find any evidence for the presence of compound 28, the
formation of hydrocarbon 6% may have come through this

primary product as follows (Equation 3;).

\V

1.5[H] <31)

 

[+11%5

52

Such a rearrangement has been reported in case of a similar
compound 22 which underwent a fast reverse Diels-Alder re-
action at 100° and gave dihydronaphthalene 8883“ (Equation

32).

1‘.)

22 mmm

(32)

V

At this stage, one experiment which seemed worthwhile was to
prepare the tosylhydrazones 68 and 101 and look at the

"u 'L’Vb
thermal and photochemical decomposition of their salts £8

and 28.

The results of these experiments were thought to be helpful
in determining the way in which hydrocarbons 8%, 3%, 88, and
88 were formed from the pyrolysis of the tosylhydrazone

salt 81. The most straightforward procedure for prepara-

tion of tosylhydrazones 88 and $81 seemed to be available

from the thermal rearrangement of tosylhydrazone 8%.

Thermal Rearrangement of [6.1.0] System.

Thermal rearrangement of bicyclo[6.l.0]—2,A,6-triene and
its 9-substituted derivatives have been reported in the
literature. Vogel and collaborators synthesized gig-bicyclo
[6.1.0]nona-2,A,6-triene 888 in 1961, and discovered its
rearrangement to a 9:1 mixture of pig and trans dihydro-

- n 039 r %
indene 88% and %¥£ at 90 (Lquatlon 33).

so
I” ""“5’ -+ (33)

102 10
two $85

Labeling experiments showed that the formation of cis
isomer 88% may occur through the valence isomers bicyclo-

[5.2.0]nona-2,5,8-triene $88 and cis, cis, cis, cis-cyclo-
A0

 

nonatetraene 106 while the trans isomer 10A is formed
’b’b’b —_ 'V'b’b

through the cis,trans,cis,cis-cyclononatetraene 88x (Equa-

 

tion 35). Thermolysis of syn and anti 9-chloro-bicyclo-
A1

 

[6.1.0]nona-2,u,6-trienes 888 and %82 led to the forma—

tion of compound $88 (Equation 35). Despite this evi-
dence, deuterium labeling studies showed conclusively

I
that 888 and 88% reacted by different mechanisms

 

 

 

[.4
O
l\)
F-J

 

 

153?,
(3”)
V/
/
\ / 9
1221 $1 10%

(Equations 36,37).

cn
35582 (1:? (35)
C' 110
1%

U1
U1

 

Cl
' [5’ Cl

~~~~ 112%

 

V'
CY, t:
V

(37)
108d ,5 C'
N’b’b’b
111
’b'V’b

The formation of compound 11% was explained according to

Vogel and Iiefer's pOStulated mechanism (Equation 38),

// _______. PHD)
< H. <——> .1

 

 

 

 

c mm
108
’b’b’b

(38)

\/
”(14(0) < a
H C" _ [4(0)
111 c:

WNW

56

while it was proposed that compound 110% was formed through

the intermediate 112.”1
WWW

Several other anti C—9-substituted derivatives (CN, OCHB,
C020H3, C6H5) have been reported to rearrange to the di-
hydroindene systems.142 In the case of antif9—substituted
fluoro and dimethylamino derivatives, the rearrangement

L43

to a mixture of dihydroindenes and syn-

*

surprisingly led
9-fluoro and dimethylamino [U.2.l]nona—2,4,7-trienes (Figure

17). The formation of the syn epimer was consistent with

“3

a suprafacial [1,5] sigmatrOpic shift.’

Some 9-cyano-9-methyl derivatives also rearranged to

H“

the [9.2.1] systems. However, the [1,3] path was pre-

UM

ferred over the [1,5] shift (Equation 39). An explanation

for these results has been presented in terms of a step-

. uu
wise biradical mechanism.

“5

Compound 118 has also been reported to thermolize

Vt?»

to the corresponding [4.2.1] system 119 (Equation U0).
Thermolysis of tosylhydrazone 63 in the presence of sodium
methoxide in tetraglyme has been reported by T. Reitzll

to lead to a mixture of dihydroindene and bicyclo[u.2.1]

-4

U]

C~1r~+ Eb

X::CN x
0CH3 x
x
C02CH3
CH x
6 5
F x x
NMez x x
Figure 17 Dearrangement of some [6.1.0] derivatives to the
dihydroindene and [3.2.1] systems.

HSC CN NC “3 "3c N
\ ————-> / + + (:Q

CN CH3
a; at W W
4.8% 120% 33.1%
NC H3 NC ”3 ”ac N _ (39)
\ ——-> / + @ + .
C CH
1 - 116 3
8:235, 3710» rvvx. 1&1

1 5 ' 9% 2.00/0 70 4%

58

 

11% 112

system with the syn pyrazole 6% as the major product (Equa-

tion 91).

 

A
Q; éé it

These results and also the formation of pyrazoles 6% and

 

6Q in the pyrolysis of the tosylhydrazone lithium salt g1
showed that the isomerization of the [6.1.0] system to
[b.2.1] might be general for substituents having n-electron
accepting groups. As a result, we thought that the most
straightforward method for the preparation of tosylhydra-
zones éé and 10% might be through the thermolysis of tosyl-

hy razone 63.

59

Thermal Rearrangement of Tosylhydrazone 63. Preparation

 

 

 

Tosylhydrazone 65

 

Tosylhydrazone 63 was thermolized in refluxing chloro-
form. The progress of the reaction was monitored by proton
nmr spectroscopy by observing the disappearance of the
doublet at 1.6 ppm belonging to cyclopropane ring and
formation of two singlets at 5.1 and 5.2 ppm characteristic

I
of the [9.2.1] systems.33’34

Integration at these two
peaks showed the presence of two epimers in a ratio of

3:1. Separation of these two isomers by column chromato-
graphy fai ed due to the polymerization of products. The
major product was separated by fractional crystallization as
a light creamy solid (yield, 99%), and was identified as
the syn—tosylhydrazone 65 from its spectroscopic informa-
tion. MP 151-1580, mass spectrum m/e, M+ 3M0, ir (Nujol):
3100, 1670, 1550, 1350, 1175, proton nmr (5,00013): 2.UH
(shs,3H), 3.0 (t,J=6.0 Hz,lH), 3.18 (m,2H), 5.2 (shs,2H),
5.3-6.1 (m,6H), 7.1-7.9 (m,6H), proton decoupled 130 nmr
(6,00013): 150.1 (10), 194.0 (10), 1&2.8 (10), 135.3

(10), 13u.2 (2C), 129.5 (20), 127.8 (2C), 127.0 (10), 126.0
(20), 123.0 (20), 47.3 (20), 39.8 (10), and 21.5 (10).

The assignment of this isomer as the syn epimer was based
on the observed coupling constant (J=6.0 Hz) for the bridge

proton at 3.0 ppm,33,3u

60

Unfortunately, attempts to isolate the Eng; epimer
101 failed because of its contamination with some gyn
epimer. Proton nmr did not detect the presence of any di-
hydroindene tosylhydrazone derivatives.

The formation of both epimers suggested that the re—
arrangement occurred either through a nonconcerted biradi-
cal mechanism or a combination of nonconcerted and concerted
allowed [1,5] sigmatropic shifts resulting in the formation
of nyn—epimer 65 as the major product.

Pyrolysis of Trans-B-[syn-bicyclo[b.2.1]nona-2,u,7-trieny1]

Acrolein Tosylhydrazone Lithium Sal§_93. Preparation of

 

Diene_5§ and Pyrazoleég

Thermal decomposition of the tosylhydrazone lithium
salt 93 was carried out in a similar way to that of salt
51 at 250°. GC/MS analysis of the volatiles showed one
single peak with a parent peak of 156 corresponding to
(CH)12 hydrocarbons (yield, 2.0-2.5%). Proton nmr showed
this compound to be diene éé' The less volatile product
was identified as the nyn—pyrazole 5% according to its
mass and proton nmr spectra (yield, 13.2%) (Equation'ft‘g).

These results clearly showed that the decomposition
of salt 93 has produced the diazo intermediate 9% which
could give pyrazole 5% by cyclization, or diene 5% through

carbene 96 and cyclopropene §5 followed by intramolecular

61

. \
» \
/ > / + I (112)
«92

 

Diels-Alder reaction (Figure 18).

This experiment also ruled out the formation of tetra-
enes 1% and 22 through the carbene intermediate 96. As
a result, both tetraenes 1% and 22 could have arisen through

the carbene 76 in the pyrolysis of tosylhydrazone salt

521-

Photolysis of the Sodium Salt of Trans-B-[syn-bicyclo-

 

[U.2.l]nona-2,u,7-trienyl]Acrolein Tosylhydrazone 65.
ab

Preparation of Diene_§8

 

Photolysis of the sodium salt f tosylhydrazone 65
either in refluxing tetrahydrofuran through a Pyrex filter
using a sun lamp or in tetrahydrofuran at room tempera-
ture through a quartz filter using a 200 W mercury lamp
gave the pyrazole 5% in 37% and 28% yield, respectively.
Nevertheless, the photolysis in tetrahydrofuran at 0° through
a Pyrex filter gave the diene 58, obtained in 31-33% yield

(Equation 93).

62

 

33 91

” HN’N\
a; /
a a:

58

’L’b

Figure 18. Mechanism for the formation of diene 58 and

pyrazole 53 from the pyrolysis of salt 93.

63

 

1'
._NNTS
1)Na+l
(U
2)hv.o° 9 / 3)
65
m 2.8.

GC/MS and nmr analysis showed no evidence for the presence
of any other (CH)12 hydrocarbons.

The formation of diene 88 and pyrazole 89 from the
pyrolysis of tosylhydrazone salt 99 clearly evidenced the
diazo compound 9% and carbene 98 as the primary inter-
mediates. In addition, the formation of diene 98 from the
photolysis of the sodium salt of tosylhydrazone 89 also
indicated the formation of carbene 98 as the primary pro-
duct. This information showed that the generation of pyra-
zole 99 and diene 98 most likely arose from tosylhydrazone
salt intermediate 99 in the pyrolysis of the tosylhydrazone
lithium salt 88 (Path D, Scheme 3). These results also
emphasized that the Eng and nnnn tetraenes 89 and 99 were
formed from the carbene 88 in the pyrolysis of salt 91.

If we were able to obtain the other anti epimer 89%, we

 

would be in a position to generate the hydrocarbon 98 (a
new 012H12 member) photochemically and check its pyrolysis
to hydrocarbon 89.

Consequently, the general scheme (Scheme U) which best

614

 

Scheme u. Decomposition of tosylhydrazone lithium salt

21-

65

explains the pyrolysis of tosylhydrazone lithium salt

81 would be both decomposition to carbene l8, and iso-
merization to the epimeric [H.2.1] tosylhydrazone salts

99 and 98. Carbene Z8, then rearranges to both tetraenes
89 and 99, and probably to cyclopropene 5% which, on sub-
sequent pyrolysis, gives hydrocarbon 88. Decomposition of
tosylhydrazone salts 99 and 99 then proceeds to correspond—
ing diazo compounds 9% and 98 which cyclize with a [1,5]
hydrogen shift to the pyrazoles 89 and 88. Decomposition
of diazo compounds 9% and 98 by loss of nitrogen gives

two epimeric carbenes 98 and 91. The carbene 98 can cyclize
to the corresponding cyclopropene 88, and finally to the
diene 88 by an intramolecular Diels-Alder reaction. 0n the
other hand, carbene 98 can lead to the formation of hydro-
carbon 98 which subsequently undergoes a retro-Diels-Alder
followed by two consecutive [1,5] hydrogen shifts under

the pyrolytic conditions leading to hydrocarbon 89.

Summary

In continuation of our research group efforts toward
the generation of new entries into the (CH)12 energy sur-
face, we were able to regenerate the recently prepared
(CH)l2 member, and proved its structure to be the diene 88
using high resolution 250 MHZ carbon and proton nuclear
magnetic resonance spectroscopy. We also prepared a new

(CH)12 representative 88 from the known cyclopropene

hydrocarbon 8%. We have been able to find evidence for the
formation of a new (CH)l2 member 98 as the primary product
leading to hydrocarbon 89. We have developed the general
thermal rearrangement of bicyclo [6.1.0] to bicyclo [n.2.1]
systems for derivatives with strong w-electron accepting
capabilities. Using this rearrangement, we prepared pure
tosylhydrazone 88 and prepared diene 88 from it by either
thermal or photochemical decomposition of its salt. These

results clearly showed that tetraenes 89 and 88 have arisen

from a different carbene intermediate than diene 88 in the

pyrolysis of tosylhydrazone salt 88.

RESULTS AND DISCUSSION
PART B

One of the earlier preparations of a (CH)l2 hydrocarbon
involvedl46 the reaction of tropylium ion 121 with the cyclo-

pentadiene ion 122 (Equation MM).
"\J’L’L

+ G >

1 2 2
t3}, rw»

 

R1

that the reaction between the known higher

It was thought37

and lower homologues of these 6w electron aromatic ions,
namely between the cyclononatetraenide %%Q and cyclopropen-
ium ions, should likewise produce a (CH)l2 species. It

was expected that the initial product lgé, which should be

a highly reactive species, would readily undergo an internal
Diels-Alder reaction to produce tetracyclododecatriene lgz,
as a potential precursor of the truncated tetrahedrane %£§
(Equation “5). Reaction between lithium cyclononatetraenide
lgg and tetrachlorocyclopropene lg; (R = X = Cl) had been

shown by Mock to give compound fig as an unanticipated

67

product.37

68

 

69

37

Formation of compound fix was rationalized as follows

(Equation U6).

 

 

Formation of Q1 showed that, under the reaction conditions,
ring contraction of lgé proceeded in preference to intra-

molecular Diels-Alder addition to give léz.

70

In this work, we decided to try to obtain compound

léé, under suitable conditions. A product similar to 126
’L’L’b

o , L1 "1 o "7
had been isolated below room temperature 7 (squation u,).

.+ e0
12m

121 131

mmm mmm - mmm

At room temperature, compound 131 rearranged to 1&2“7
mdm m m

(Equation U8).

\
L3). 7 s , (ma)

 

132

WWW

We thought that by keeping the tetraene intact in %%é’ by
controlling the reaction temperature, it might undergo ad-
dition to the cyclopropene ring in a Diels-Alder fashion
instead of undergoing ring contraction. In addition, Mock's
isolation of compound $1 as the only product in very low
yield37 (2%) prompted us to reinvestigate the reaction.

Although the reaction was done several times, either at 0°

or -78°, nothing could be obtained except compound Q1 in

‘— A . . I“
the reported yield.

At this stage, we decided to use 3—chlorocyclopropene

H
a
cf
(1)
Q)
D
O
01)
( r
(D
U
*5
Q)
0
:5‘
[.4
O
“5
O
O
m
C.)
F4

opropene. We thought this

better electrophile which in turn might show
different results. Generation oi 3—chlorocyclopropene was
attempted by treatment of l,3-dichloropropene with strong
base. A similar reaction was reported in the literature

for preparation of cyclopropene by treatment of allyl-

b
chloride with sodium amide'8 (Equation 39).

 

CHZZCH-CHE'C‘ ; A > / (149)

12a 6
tat kiw

The generated cyclopropene was trapped with cyclopenta-

diene and resulted in the Diels-Alder adduct lgé.u8
Treatment of 1,3-dichloropr0pene with n-butyl lithium

at -U0° and subsequent reaction with cyclononatetraenide

at -78°, after purification gave a yellow oil in 30% yield.

This product was identified as compound $3 from its

8H

spectroscopic data.
MS, m/e 192 (lQH-Cl isotope), ir (neat): 3100, 2900,

1650, lBO-MHZ proton nmr (6,0001 ): 2.39 (dd,J=7.5 and 9.0

u.)
\n
\o
/‘\
0‘ w

Hz,2H), 2.65—2.75 (m,2H), d,J=l2.0 Hz,lH), 5.u7

f-

(m,lH), 5.55-9-

‘1)
\fl

(m,6H), proton decoupled 130 nmr (5,CDC7 )3

*3

72

 

CH2.—CH=CH —CI

134.1 (1C), 132.3 (10), 129.6 (10), 128.9 (10), 126.0 (10),
120.9 (10), 120.7 (10), 119.0 (10), 5M.5 (10), uu.o (10),
u1.9 (10), and 31.7 (lb). Partially proton coupled 130

nmr transformedthosesinglets at 54.5, 49.0, “1.9, and 31.7
ppm to a doublet, doublet, doublet, and a triplet, respec-
tively. This spectrum clearly showed that the carbon cor-
responding to 31.7 contained two hydrogens. The assignment
for cis-ring fusion was made on the basis of diallylic pro-
ton coupling (J=12.0 Hz) at 3.59 ppm.u9

This experiment showed that 3-chlorocyclopropene had
not been formed under the reaction conditions. This result
prompted us to prepare 3-chlorocyclopropene separately,
and then look at its reaction with lithium cyclonononatetra-
enide.

Treatment of 1,3-dichloropropene with sodium amide at
60-900, after distillation resulted in recovered starting
material. In addition, treatment with potassium t-butoxide50
led to a messy mixture which showed no evidence for the
presence of 3-chlorocyclopropene in its nmr spectrum.

Because of time limitations, we stopped these experiments,

73

although synthetic approaches toward the cyclopropenium
ion from other methods is currently in progress in our

group.

‘—
‘l

melting points were taken in Open capillaries
with a Thomas—Hoover apparatus. The NME spectra were re—

corded on a Varian T-60 (60 kHz , Bruker WH 180 MHZ, Varian

O
#11
I3
['\)
O
U
{D
:3
[D
"S
C
ED
’3
l\)
U'I
O

pectrometer operating at 250 MHZ
H and 62.86 MHZ for C. Cher. .ic a1 shifts are reported
in ppm down Iield :rom internal standard tetramethylsilane.

The J values are given in nz. Gas cnro matography/mass

spectral data were obtained on a Finnigan U021 with 11008
System eqiipped with a 1/8 in. x 6 ft glass column packed
with u% 03-225 on Cnromasorb C. Tne corpositions reported
were calculated b" comparing the peak of 1 2 3 etramethyl

by weight). gas chromatography separations were achieved
at 1200 using an F & M Model 700 c.ro matograph equ uipp ed

with a rmal conducti'it‘ detector. Helium was used as
tne carrier gas at flow rates 35-L3 ml/min. An injector

emperature of 2500

Cr
(1)
3
'O
(D
'"3
m
(T
C
*5
(D
O
H.)
l\)
r:
O
O
{D
:3
Q
1)
L).
(D
Cf
(D
O
c r
O
"5
Cf

were used in all cases. The column employed was a 1/5 in.

x 6 ft aluminum column packed with 3% OV-225 on Chromosorb

9 ~ h r: A..- ‘F’ m‘ . fl
0, aClQ rashed an s_1an- ed. _ne concentrati n o: M—
.uoyll°‘1“ ", used for preparation of the salts of tosyl—
xJGFa o . “as determired according to the procedure des-

I...
‘ v " 0 /
cribed by no-ron.

75

9:0arbethoxy bicyclo[6.1.0]-2,’J.,6-triene23 59

Ester 29 was prepared in “7% yield by treatment of cyclo-
octatetraene with ethyl diazoacetate in the presence of
copper sulfate, (bp 88-90° at 0.8 mm). Proton nmr (5,001“);
1.25 (5,J=7 Hz,3H), 1.3 (t,J=5 Hz,1H), 2.05 (d,J=5 Hz,2H),

9.1 (q,J=7 Hz,2H), 5.9 (s,2H), and 6.0 (s,HH).

 

9-Hydroxymethyl bicycloL6.l.0]nona-2,u,6—triene_603:

Alcohol 60 was prepared in 77% yield by reduction of
ester 59 with lithium aluminum hydride in ether. Recrystal-
lization of crude alcohol from hexane was found to be
cleaner than from methanol-water mixture. Np 60-6l°, proton
nmr (6,00 u): 0.78 (t,J=5.0 and 6.0 Hz,lH), 1.9 (d,J=5.0
Hz,2H), 3.6 (d,J=6.0 Hz,2H), n.55 (bs,lH, washed with 020),

5.9 (s,2H), and 6.0 (s,uH).

6123

Bicyclo[6.1.0]nona-2,U,6-triene-9—carboxaldehyde m__
‘b

 

Oxidation of alcohol 60 with chromium trioxide and
pyridine in methylene chloride yielded aldehyde 61 (75.3%,
bp 58-62° at 0.25 mm). Proton nmr (5,001“) 1.7 (dt,J=6.0
and 5.0 Hz,lH), 2.2M (d,J=5 Hz,2H), 5.9 (s,2H), 6.0 (5,
MH), and 9.7M (d,J=6 Hz,lH).

76

I;
Diethyl-2,2-diethoxyethylphosphonate 1"8’2

._m m__
Compound 13% was prepared (70% yield, bp loo-102°, 0.8
mm) by treatment of triethylphosphite with bromoacetalde-
hyde diethylacetal. Proton nmr (6,001“): 1.22 and 1.3“
(2t,J=7 Hz,12H), 2.17 (dd,J=19 and 6 Hz,2H), 3.6 (2q,J=7

Hz,“H), “.1 (2q,J=7 Hz,“H), and “.9 (q,J=6 Hz,1H).

Diethylformy1methylphosphonate 139E:

 

Treatment of compound 138 with hydrochloric acid, gave,
after work up and distillation, compound 139 in 76% yield
(bp 100-1030 at 0.8 mm). Proton nmr (5,CDC13): 1.35

t,J=7 HZ,6H), 3.11 (dd,J=22 and 3.5 HZ,2H), “.2 (2q,J=7

Hz,“H), and 9.7 (dt, J=3 and 1 Hz, 1H).

Diethyl-2-(cyclohexylamino)vinylphosphonate 1“0ll

'—'\J’\;%_

 

Treatment of compound 139 with cyclohexylamine in dry
acetonitrile according to the described procedure did not
result in compound 150. We found that the presence of un-
reacted amine prevents the crystallization of product.

As a result, we improved the procedure as follows.

After treatment of compound 139 with fresh cyclohexyl
amine at 0-5° in dry acetonitrile, the flask was left
under aspirator vacuum at 100° for one hour. The residue

was then taken up in 300 ml ether and dried over anhydrous

77

sodium sulfate. The ether was partly evaporated so that
the volume of the solute to the solvent became 1:1. This
solution was then put in the freezer (-“0°) for several
days. Crystallization yielded compound 1“0 as a white
solid (70% yield mp 60-620). Proton nmr (6,CDCl3): 1.0-
2.1 (m overlapped with a triplet at 1.3 (J=7 Hz, 17H),
“.0 (quintuplet, J=7 Hz, “H), “.8-5.2 (bs, NH), and 6.6-

7.“ (m, 2H). -

Trans-B-[anti-9-bicyclo[6.1.0]nona-2,“,6-Trieny1]Acrolein

11
8%..

Condensation of compound 130 with aldehyde 6% in the
presence of sodium hydride according to the reported pro-
cedure resulted in the formation of extended aldehyde 62
in low yield (m20%) contrary to the reported 68% yield.11
When the mixture of aldehyde and enamine was stirred over-
night and the final dark solution was concentrated before
working up the yield increased to the reported value. Mp
88—90°, proton nmr (6,CDCl3): 1.69 (m, 1H), 1.9 (d, J=5
Hz, 2H), 5.9 (s, 2H), 6.0 (s, “H), 6.25-6.“5 (2d, J=7.5

Hz, 2H), and 9.“ (d, J=7.5 Hz, 1H).

Trans-B-[anti-9-bicyclof6.1.0]nona-2,“,6-trienyl]Acrolein

Tosylhydrazone 63

 

Tosylhydrazone 63 was prepared in 8“% yield by treat-

ment of aldehyde 6% with p-toluenesulfonhydrazide in the

presence of acetic acid in ethanol. Mp 1“9—150°, proton

nmr (6,0D01 ): 1.2 (m, 1H), 1.65 (d, J=5 Hz, 2H), 2.“

3
(s, 3H), 5.7-6.“ (m, 8H), and 7.3-8.1 (m, 6H).

Preparation of Tosylhydrazone Lithium Salt 5;

In a 100 m1 three necked round-bottomed flask equipped
with a magnetic stirrer, 100 m1 dropping funnel, and nitro-
gen inlet, was placed 0.5 g (l.“7 mmoles) tosylhydrazone
63 in 10 ml anhydrous tetrahydrofuran. The flask was
flushed with nitrogen and the solution was cooled to -78°
in a dry ice-acetone bath. 1.0 ml of n-butyl lithium in
hexane (1.“7 N) was slowly added through the ropping
funnel. A tannish yellow color developed, and a precipitate
fell out immediately. After the addition was finished,
the solution was kept at -78° for 15 min, then slowly
warmed to room temperature, and allowed to stir another
15 min. 60 ml pentane was added and the mixture was
filtered. The lithium salt was obtained as a yellow solid
in a nearly quantitative yield. This salt is stable in

air and can be stored for a long time.

79

Pyrolysis of Tosylhydrazone Lithium salt 51. Preparation

of Exo-tricycloE“.“.2.02’5]dodeca-3,7,9,ll-tetraene l“,

 

Endo-tricycloE“.“.2.02’53dodeca-3,7,9,ll-tetraene 22,
.U—

02’12.03’7.Ou’ll

pentacycloE6.“.0. jdodeca:5,9-diene58L

 

1,2-Benzocycloocta-l,3,7-triene 6“, and 9-syn and anti(5-

pyrazola)bicyclo[“.2.l]nona-2,“,7-triene 5“ and 52

 

Tosylhydrazone lithium salt 57 (0.5 g, 1.““ mmoles)
was placed in a bent Pyrex tube with a male ground glass
joint and attached to the pyrolysis apparatus (Figure 19).
The system was opened to vacuum (ca. 0.03 mm Hg), and the
sand bath heated to 250°. The lithium salt was added in
small portions to the flask containing hot glass beads.
Periodically, approximately 5 to 10 glass beads were added
to the flask to give fresh surface. New beads were allowed
to warm up for about 20 minutes, before addition of more
lithium salt. After addition of all lithium salt (ap-
proximately 2 hours), the system was cooled to room tem-
perature, the vacuum was disconnected, and nitrogen was
slowly allowed into the apparatus. It was observed that
some less volatile compounds were deposited on the exten-
sion tube. This portion was separately washed into a flask
with methylene chloride. The contents of the liquid
nitrogen trap were washed with methylene chloride into
another flask. This solution was concentrated on a rotary
evaporator and subjected to gc/ms analysis. Five peaks

were evident at 9.2, 12.8, 16.6, 18.3, and 33.“ minutes in

80

/"

 

Li.salt ‘13" 1
I ’ "92;.
o glass beads
liquid.N ...,vacuum pump
,2? 3 ’4’ 2
: trap
N.Nflot '

g

\ '*
‘~ ‘”
-.3~= S"-

-sand bat h
(250°)

31H m”
{I 3m

tsti'

 

you

$5
3

Figure 19. Pyrolysis apparatus for decomposition of dry

salt 51.

a ratio of 1.2:6.8:7.5:l3.5:3.3, respectively. Mass spec-
tra exhibited parent peaks of 156 for (CH)12's. All these
compounds were separated on preparative columns. There was
not enough of the first compound to be identified. The
second compound was isolated as a white solid (3% yield),
and identified to be diene pg. Mp 67-68011, ms (m/e, %):
156 (20), 155 (“9), 15“ (16), 153 (31), 152 (28), l“1 (39),
129 (20), 128 (“1), 127 (18), 115 (31), 91 (100), 78 (13),
77 (7), 250 MHz proton nmr (5,00013): 1.75 (dt, J=7.0

and “.7 HZ, 1H), 1.91 (ddd, J=7.0, 5.5, and 1.5 Hz, 2H),

81

2.9 (m, 2H), 3.15 (ddd, J=9.3, 5.5, and 1.5 Hz, 2H), 3.35
(dt, J=5.5 and “.7 Hz, 1H), 5.u5 (t, J=l.2 Hz, 2H), 6.05

‘2
140 nmr (5,

(dd, J=5.8 and 2.8 Hz, 2H), proton decoupled
CDCl3): 13u.8 (2C), 131.3 (2o), 66.3 (10), 62.6 (20),

u1.8 (20), 36.1 (20), 26.6 (10), proton coupled l3c nmr
(6,0DC13): 13u.6 (d, J=l60.9 Hz, 2c), 131.1 (d, J=l56.“

Hz, 2C), 66.2 (d, J=137.8 HZ, 1C), 62.3 (d, J=137.8 Hz,

20), “1.6 (d, J=135.9 Hz, 20), 36.06 (d, J=l66.5 Hz, 20),
and 26.“ (d, J=17l.l Hz, 1C).

The third compound was isolated as a clear liquid
(yield 3.3%) and identified from its nmr as the known exo-
tetraene l“.9b Ms (m/e, 7): 156 (“7), 155 (68), 153 (“3).
152 (31), 1“1 (51), 128 (59), 115 (“6), 91 (100), 78 (16),
60 MHz proton nmr (6,001“): 2.57 (m, 2H), 3.25 (bs, 2H),
5.3-5.“ (dd, J=5 and 2.5 Hz, 2H), 5.83 (shs, 2H), and 5.0-
5.9 (m, “H).

The fourth compound was isolated as a white solid
(yield 6%), and identified as endo-tetraene 22.1“ Ms
(m/e, %): 155 (6), 155 (“7), 15“ (22), 153 (“8), 152 (29),
1“1 (“7), 129 (30), 128 (62), 115 (“8), 91 (100), 78 (16),
60 MHz proton nmr (6,001“): 2.82 (bs, “H), 5.“-5.6 (m,
6H), and 6.0“ (shs, 2H).

The last compound was isolated as a yellow liquid (yield
1.5%). The spectral data showed it to be 1,2-benzocyclo-

2“

octa-l,3,7-triene 6“. MS (m/e, %): 156 (3“), 155 (22),

82

15“ (12), 153 (23), 152 (19), 1“1 (29), 129 (20), 128 (100),
115 (22), 250 MHZ proton nmr (5, CDC13): 2.29 (m, “H),

5.92 (m, 2H), 6.52 (d, J=12.3 Hz, 2H), 7.13 (m, 2H), 7.22
(m, 2H), proton decoupled 130 nmr (5, 00013): l“3.6 (20),
136.7 (2c), 131.2 (2c), 130.6 (2c), l2“.3 (2c), and 25.“

(2c).

Spin Decoupling Studies of Diene 58
'U

Using 250 MHZ proton nmr, decoupling experiments were
carried out at seven positions. Irradiation at 1.75 ppm
caused the doublet of doublet of doublets at 1.91 ppm,
and doublet of triplets at 3.35 ppm to collapse to a doub-
let of doublets (J=5.5 and 1.5 HZ) and a triplet (J=
5.5 Hz). Irradiation at 1.91 ppm caused the doublet of
triplets at 1.75 ppm to collapse to a distorted doublet
(J=“.7 HZ) and also caused some change in the multiplet
at 2.9 ppm. Irradiation at 3.35 ppm collapsed the doublet
of triplets at 1.75 ppm and doublet of doublet of doublets
at 3.15 ppm to a triplet (J=7.0 Hz) and a doublet of doub-
lets (J=9.3 and 1.5 Hz). These results clearly showed that
the proton at 1.75 ppm had vicinal coupling relations both
with two protons at 1.91 ppm (with J=7.0 Hz) and the single
proton at 3.35 ppm (with J=“.7 Hz). Thus, the signals at
1.75 were assigned to cyclopropane ring proton H2. Ir-
radiation at 2.9 ppm caused the doublet of doublet of

doublets at 1.91 ppm, doublet of doublet of doublets at

83

3.15 ppm, and doublet of doublets at 6.05 ppm to collapse
to a doublet of doublets (J=7.0 and 1.5 Hz), a broad doub-
let (J=5.5 HZ), and a sharp singlet respectively. As a
result, the two protons at 1.91 ppm must have vicinal coupl-
ing relation with the two protons at 2.9 ppm (with J=5.5
Hz). These two protons were assigned to the H1 and H12

of the cyclopropane ring. The additional coupling (J=l.5
HZ) may be either a long range or a second order coupling.
0n the basis of these results, the two protons at 2.9 ppm
was also found to have vicinal relations both with the
pairs at 3.15 ppm (J=9.3 Hz) and 6.05 ppm (J=5.8). So
these two were assigned to the bridgehead protons H8 and

H while the signals at 6.05 ppm were assigned to protons

11’

H9 and H10.

collapsed to a singlet after irradiating at 2.9 ppm, the

Since the doublet of doublets at 6.05 ppm

second coupling (J=2.8 HZ) should have arisen from the
long range allylic coupling of H10 with H8. The assignment

of signals at 6.05 ppm to H9 and H10 were supported by
irradiating at these signals and observing some distortion in
thewmltiplet at 2.9 ppm as the only Change in the spectrum.
Irradiation at 3.15 ppm collapsed the doublet of triplets

at 3.35 ppm and the triplet at 5.“5 ppm to a doublet (with
J=“.7 Hz) and a sharp singlet, respectively. So, it was
realized that this pair should also be related vicinally to

the single proton at 3.35 ppm. This pair was assigned to

the bridgehead protons H“ and H7, while the two olefinic

8“
at 5.“5 ppm were assigned to H5 and H6. Collapse of
the triplet at 5.“5 ppm to a singlet after irradiation
at 3.15 ppm, clearly showed that this triplet must have
been the overlap of two doublets of doublets, one resulted
from vicinal coupling of H5 with H“ (J = 1.5 Hz), and the

other from long range allylic coupling of H with H“ (J =

5
1.2 Hz).

The less v01atile part was flash chromatographed on
silica gel with ether elution. The first eluting material,
which was not characterized, was observed by its nmr spec—
trum to be an aromatic compound. The second eluting com-
pound was obtained as a yellow greasy material (6.7 mg,
yield 2.2%). This compound was identified as anti-
pyrazole 55 from its spectroscopic data. MS (m/e, %):

18“ (16), 183 (19), 169 (9), 156 (12), 128 (9), 115 (“0).
91 (35), “0 (100), 60 MHZ proton nmr (6, 00013): 2.95 (s,
1H), 3.12 (d, J=6.0 Hz, 2H), 5.08 (s, 2H), 5.6-6.1 (m, 5H),
6.98-7.l (m, 2H), proton decoupled l3C nmr (6, CDC13):
137.75 (20), l2“.26 (2C), 121.21 (20), 50.08 (20), and
“0.22 (10). Because of a noisy baseline, the peaks
belonging to the pyrazole ring were not observed.

The third eluting material was separated as a yellow
greasy compound (17.5 mg, yield 6.1%). This compound was

identified as the syn-pyrazole 5“ from its spectroscopic

information. MS (m/e, %): 18“ (16), 183 (22), 169 (10),

85

156 (13), 128 (10), 115 (37), 91 (3M), “0 (100), 60 MHZ
proton nmr (0, 00013): 3.1-3.“ (m, 3H), 5.12 (s, 2H),

5.8 (bs, 5H), 7.1 (m, 1H), 11.0 (bs, 1H), proton decoupled
13c nmr (a, 09013); 1u5.69 (small), 135.uu (26), 13“.“8
(small), 126.09 (2c), 122.87 (2c), 10“.20 (small), “6.37

(20), and 36.07 (10).

Anti-9r(AE-cyclopropeno)-bicyclo[6.1.0]nona-2,“,6—triene

 

51.23 Low temperature Photolytic Decomposition of Tosyl-

hydrazone Sodium Salt “9
WW

 

This procedure was adapted from Raghu's thesis.23 The
tosylhydrazone 63 (3“0 mg, 10 mmoles) was dissolved in 60
ml dry tetrahydrofuran and was placed in a Pyrex tube
equipped with a magnetic stirrer and nitrogen inlet.
Sodium methoxide (5“ mg, 10 mmoles) was added to this and
allowed to stir for 10 minutes. The tube was then placed
next to a Pyrex immersion well in a dry ice-acetone bath.
The solution was photolyzed using a 200 W Hg vapor lamp
for 2.5 hours. The solution was poured into 300 m1 of ice
water and 200 m1 of pentane. The pentane layer was sep-
arated, and the aqueous layer was extracted with another
100 ml of pentane. The combined pentane extracts were
washed with 100 ml cold water to remove most of the tetra-
hydrofuran. The solution was dried over anhydrous sodium
sulfate and then rapidly filtered through silica gel (W20 g)

to remove unreacted tosylhydrazone. The solution was

86

concentrated to 5 m1 on a rotary evaporator and the rest of
solvent was removed at -30° using a high vacuum pump to
give 58 mg of a light yellow oil (yield, 37%). This com-
pound was shown to be cyclopropene 51 according to its

nmr spectrum. 60 MHZ proton nmr (5, CD013) showed peaks
at: 0.8—1.0 (m, 1H), 1.2 (d, J=5.5 HZ, 2H), 1.8 (m, 1H),

5.8-6.0 (d, 6H), and 7.2 (shs, 2H).

Pyrolytic Attempts at Isomerizing Compound 51
’b
Method A

A 60 cm Pyrex tube, packed with 25 cm of glass beads,
and fitted with a serum cap at the top was connected from
the bottom to a trap kept in liquid nitrogen. The system
was opened to vacuum (ca. 0.3 mm Hg), and the tube was
heated to 300° with an tube oven. Hydrocarbon 51 (52 mg,
0.3 mmoles) was dissolved in 2 ml dry tetrahydrofuran and
was injected through the serum cap in small portions.
After finishing the addition (around two hours), the oven
was cooled to room temperature, and the vacuum was dis-
connected. The contents of the trap were rinsed with
pentane into a flask. Most of the solvent was removed on
a rotary evaporator and the rest was taken off at —30°
using a high vacuum. Proton nmr spectrum showed it to be
the recovered starting material. Gc/ms analysis showed no

evidence for any other (CH)l2 hydrocarbons.

87

Method B

A 250 ml round bottomed three necked flask equipped
with a serum cap and stopper, and containing glass beads
was connected to a trap kept in liquid nitrogen. The
flask was opened to vacuum (ca. 0.3 mm Hg), and heated to
300° in a sand bath. Hydrocarbon 51 (52 mg, 0.3 mmoles)
was dissolved in 2 ml dry tetrahydrofuran, and was in-
jected through the serum cap. After injecting all the
solution (ca 2 hrs), the flask was cooled to room tempera-
ture, and the vacuum was disconnected. Proton nmr spectrum
of the contents of the trap revealed only the starting

material.

Method C

Hydrocarbon 51 (53 mg, 0.3 mmoles) was dissolved in
pentane (10 ml) and the solution was placed in a 60 cm
Pyrex tube. The tube was sealed under nitrogen and was
placed in the oven and then rapidly heated to 260°. The
solution was allowed to stand at this temperature for 5
minutes. It was observed that a polymeric material was
deposited on the tube wall which was not soluble in organic
solvents. The nmr spectrum of the concentrated solution
was quite messy and gc/ms analysis showed no evidence for

(CH)l2 hydrocarbons.

88

Method D

2,u 3,10

Preparation of Pentacyclo[6.“.0.0 .05’93dodeca-

0
6,1l-diene 86 - A 60 cm pyrex tube, packed with 25 cm

of glass beads was connected to a 250 m1 round bottomed

three necked flask containing glass beads, serum cap, and

argon inlet. The top of the column was connected to the

trap kept in liquid nitrogen (Figure 20).

“Quid -N2 --> vacuum pump
trap

 

  
  
 

——tube ovon(3oo°)

 

glass beads

 

 

,serum cap
argoanlet

(300°)

Figure 20. Pyrolysis apparatus for isomerization of com-
pound 51.

89

Argon was allowed to flow into the apparatus and the system
was opened to vacuum (ca. 0.3 mm Hg). The flask and tube
were then heated to 300° with a sand bath and tube oven
respectively. Hydrocarbon 5% (52 mg, 0.3 mmoles) was dis-
solved in 2 m1 dry tetrahydrofuran and was injected through
the serum cap into the hot flask. After injecting all the
solution (2 hours), the system was cooled to room tempera-
ture, and the vacuum was disconnected. The contents of the

trap were rinsed with pentane into a flask and the solution

was concentrated at -20° using a high vacuum pump. Gc/ms
analysis showed two peaks at 9.20 and ll.“0 minutes in a
ratio of l“.0:3.2. Mass spectra taken at these peaks showed
a parent peak of 156 corresponding to (CH)l2 hydrocarbons,
The first compound was collected by preparative gas chroma-
tography as a colorless liquid (1.5 mg, yield 2.6%). This
compound was identified as polycyclic 55 from its spectro-
scopic data. MS (m/e, %): 156 (10), 155 (ll), l“1 (11),
128 (1“), 115 (15), 91 (100), 78 (16), 250 MHZ proton nmr
(a, 00013): 0.7-0.9 (m, 2H), 1.75 (ddd, J=7.9, “.9, and
u.1 Hz, 1H), 1.85 (dd, J=6.2 and 3.3 Hz, 1H), 2.35 (ddd,
J=7.5, 6.2, and 5.1 Hz, 1H), 2.“8 (dd, J=7.9, and 6.2 Hz,
1H), 2.82 (dd, J=5.l, and 3.2 HZ, 1H), 3.06 (dd, J=7.5 and
5.8 Hz, 1H), 5.55 (dd, J=5.0 and 3.3 Hz, 1H), 6.12 (dd,
J=5.0 and 3.2 Hz, 1H), 6.33 (dd, J=7.9 and 5.8 Hz, 1H),

and 6.55 (dd, J=7.9 and 6.2 HZ, 1H).

90

Preparation of Trans-B-[syn-9-bicycloE“.2.1]nona-2,“,7-

 

trienyllAcrolein Tosylhydrazone_55

 

Tosylhydrazone 5 (1.0 g, 2.9 mmoles) was refluxed in
50 ml chloroform overnight. Solvent was removed by rotary
evaporator and the residue was crystallized in a mixture
of methylene chloride and carbon tetrachloride to give 2“0
mg of a light yellow solid. The mother liquid was concen-
trated and crystallized in a mixture of methylene chloride
and hexane to give another 220 mg of the solid (“9%, mp
151-153°). This compound was identified as the titled
compound 55 from its spectra. MS (m/e, %): 3“0 (2.“),
278 (9.8), 2A9 (“), 185 (63), 168 (10), 156 (2“), 155 (ll),
l“l (17), 129 (17), 115 (28), 91 (100), 81 (2“), 77 (12),
ir (Nujol), 3100, 1670, 550, 1390, 1350, 1310, 1180, 60 MHZ
proton nmr (0, 00013): 2.“ (s, 3H), 3.0 (t, J=6.0 HZ, 1H),
3.18 (m, 2H), 5.1 (shs, 2H), 5.7-6.0 (m, 6H), 7.1-8.0 (m,
6H), proton decoupled 130 nmr (a, 00013): 150.1 (10), 1““.0
(10), 1“2.8 (10), 135.3 (1C), l3“.2 (2C), 129.5 (20), 127.8
(20), 127.0 (10), 126.0 (20), 123.0 (20), “7.3 (2C), 39.8
(10), and 21.5 (1C).

The filtrate was concentrated and was shown by nmr to
be a mixture of compound 55 and its epimeric compound 55%.
Fractional crystallization failed to separate these epi-

mers .

91
Preparation of Trans—B:£syn-9-bicyclo£“.2.11nona-2,“,7—
trieny11Acrolein Tosylhydrazone Lithium Salt 95
fifib

Tosylhydrazone lithium salt 55 was prepared according
to the procedure described for the lithium salt 55 and ob-

tained in a nearly quantitative yield.

Pyrolysis of Tosylhydrazone Lithium Salt 95. Preparation
‘U

 

of Diene 5g and Pyrazolem5g

Tosylhydrazone lithium salt 55 (0.5 g, 1.““ mmoles) was

pyrolyzed at 250° in the same way described for lithium salt

51 (Figure 17). Gc/ms analysis of voltailes showed a

single peak at 12.8 minutes with a parent peak of 156.

Proton nmr spectrum showed this to be the diene 55 (yield,

1.9-2.3%). Analysis of the less volatiles showed the pres-

ence of the pyrazole 55 (yield 13.2%).

Photolysis of Sodium Salt of Tosylhydrazone_55. Preparation

 

of Pyrazole 55

 

In a 500 ml round bottomed three necked flask equipped
with a magnetic stirrer, condenser, and nitrogen inlet,
was placed a solution of tosylhydrazone 55 (100 mg, 0.27
mmoles) in 10 m1 dry tetrahydrofuran. Ninety-nine percent
sodium hydride (7.0 mg, 0.27 mmoles) was added to this solu-
tion and the mixture was allowed to stir for 15 minutes. The

flask was then placed close to a sun lamp and was irradiated

92

for one hour. During this time, the solution began to reflux.
The solution was filtered to remove the unreacted salt and
the filtrate was concentrated at -20° using a high vacuum

pump. Mass spectra and proton nmr showed the product to be

the pyrazole 5% (20 mg, 37%).

Photolysis of the Sodium Salt of Tosylhydrazoneéé Through

 

a Quartz Filter Usingia 200 w Hg Vapor Lamp. Preparation

of Pyrazole 5%

 

A solution of tosylhydrazone $5 (100 mg, 0.2 mmoles)
in 60 ml tetrahydrofuran was placed in a Pyrex tube con-
taining a magnetic stirrer, and nitrogen inlet. The tube
was flushed with nitrogen and 99% sodium hydride (7 mg,
0.27 mmoles) was added to the solution and allowed to stir
for 15 minutes. This solution was then placed close to a
quartz immersion well and photolyzed for one hour using
a 200 W Hg vapor lamp. The solution was then poured to a
mixture of 200 ml ice water and 200 ml of pentane. The
pentane layer was separated and the aqueous layer was ex-
tracted with another 100 ml of pentane. The combined
pentane extracts were washed with 100 ml cold water to
remove most of the tetrahydrofuran. The solution was
dried over anhydrous sodium sulfate. The solution was
filtered and most of the solvent was removed on a rotary
evaporator. The rest of the solvent was removed at -30°
using a high vacuum pump. Mass spectra and nmr showed the

product to be the pyrazole 55 (15 mg, yield 28%).

93

Low Temperature Photolysis of the Sodium Salt of Tosyl-
hydrazone $5 Through a Pyrex Filter with 200 W Hg Vapor

Lamp. Preparation of Diene_58

 

This experiment was carried out in the same way as
described above with the exceptions that the reaction
was run at 0° and irradiation was done through a Pyrex
filter. Gc/ms analysis of the product showed a single
peak at 12.8 minutes with a molecular ion peak of 15$
(yield 31-33%). The proton nmr spectrum was identical

with that of diene 58.

Pentachlorocyclopropane 13153
a” —-

 

Compound 13% was prepared by treatment of trichloro-
acetic acid sodium salt with trichloroethylene, obtained
in 22.U% yield (bp 35° at 1.0 mm Hg). Ir (neat): 3000,
960, 930, 900, 770, proton nmr (5, 0C1“): 3.8, sharp

singlet.

Tetrachlorocycloppopene 1255:

u
Compound 122 was prepared by treatment of compound 1N1
with potassium hydroxide, and then hydrochloric acid, ob-
tained in 80% yield (bp 129-131 at 7&5 mm Hg). IR (neat):
2300, 1150, 1050, and 750.

9H

- 5U
Anti-9-Chlorobicyclo[6.l.0)nona-2,u,6-triene 1U2

'b’b’b

 

Compound 13% was prepared in 2H% yield (bp 31-32° at
0.3 mm) according to the described procedure. Proton nmr
(6, 0C1“): 1.8 (d, J=U.0 Hz, 2H), 2.U (t, J=u.0 Hz, 1H),
5.9 (s, 2H), and 5.95 (s, 4H).

Preparation of 2,3,U-Trichloropentacyclo[6.H.0.02’u.03’lo—

 

.05’9Jdodeca—6,ll—diene 87.37
_“\1

 

To a magnetically stirred mixture of 1.05 g lithium
(cut into small pieces in an argon atmosphere, washed with
cyclohexane, and added directly to the reaction flask con-
taining solvent and argon atmosphere) and 50 ml of dry
tetrahydrofuran was added 9.8 g (0.06Umoles)of 9-chloro-
bicyclo[6.l.0]nona-2,u,6-triene 132 in 30 ml of tetra-
hydrofuran. The final black reaction mixture which con-
tained a few particles of unreacted lithium was added with
a syringe to a solution of 38.5 g (0.2lmoles)of tetrachloro-
cyclopropene 125 in 350 ml of tetrahydrofuran at 0° over a
period of 15 minutes. The mixture was allowed to stand
overnight at room temperature. The solvent was removed on
a rotary evaporator, and the residue was treated with water
and extracted with methylene chloride. The organic ex-
tract was dried over anhydrous sodium sulfate and con-
centrated on a rotary evaporator. A small amount of un-
reacted tetrachlorocyclopropene was removed using a high

vacuum pump. The final thick oily black residue was taken

95

up in carbon tetrachloride and submitted to column chroma-
tography on 200 g of silica gel with carbon tetrachloride
elution. Analysis of different fractions with TLC and nmr
showed them to be polymeric materials. Elution was then
continued with chloroform.

TLC showed some fractions contained a major compound.
The nmr spectrum showed it to be the reported compound 81.
(53 mg, yield 1.8%). 60 MHz proton nmr (6, CD013): 2.0
(bd, J=7.0 Hz, 1H), 2.u5 (ddd, J=7.0, 6.0 and 5.0 Hz, 1H),
2.8 (dd, J=6.0 and 2.0 Hz, 1H), 3.2 (dd, J=6.0 and 3.0 Hz,
1H), 3.uo (dd, J=6.0 and 6.0 Hz, 1H), 5.7 (dd, J=6.o and
3.0 Hz, 1H), 6.0 (dd, J=6.0 and 3.0 Hz, 1H), 6.2 (dd, J=

7.0 and 5.5 Hz, 1H), and 6.“ (dd, J=7.0 and 6.0 Hz, 1H).

Temperature Effect on the Formation of Compound_87

The cyclononatetraenide solution was_orepared and then
transferred to a dropping funnel containing a cooling jacket.
This solution and the solution of tetrachlorocyclopropene in
tetrahydrofuran were cooled to -78° using a dry ice-acetone
bath. The cyclononatetraenide solution then was added to the
flask over a period of 1.5 hours. The reaction mixture
was allowed to stand at -78° for another 3 hours, and then
gradually brought to room temperature. The mixture was
then stirred for 2 days at room temperature. This solu-
tion was poured into 300 ml of ice water and 500 ml of ether.

The ether layer was separated, and the aqueous layer was

96

extracted with two 250 ml portions of ether. The ether
extracts were combined, washed with 200 ml of ice water,

and dried over anhydrous sodium sulfate. Ether was re-
moved on a rotary evaporator, and the final black residue
was submitted to chromatography on 200 g silica gel. Elut-
ing with carbon tetrachloride and chloroform finally yielded

the compound 87 in the same yield (1.8%).

Preparation of 1-Chloro-3—(dihydroindene)-l-Propene 131

Into a 500 ml round bottomed three necked flask equipped
with magnetic stirrer, dropping funnel, dropping funnel with
cooling jacket, and nitrogen inlet, was placed 3.A g (0.03

moles} of 1,3-dichloropropene in 100 ml dry ether. The solu-
tion was cooled to -A0° using a dry ice-acetone bath. 21
m1 of n-butyl lithium (1.6 N) was added through the dropping
funnel over one hour. A yellow color developed followed
by the precipitation of lithium chloride. The mixture was
then warmed to 0° and left standing for five hours. The
mixture was then cooled to -78° in dry-ice-acetone bath and
to this was added a solution of lithium cyclononatetraenide
(prepared by treatment of 2.1 g (0.01Amoles)of éflél‘9'
chloro-bicyclo[6.1.0]nona-2,u,6-triene with 0.25 g lithium
in tetrahydrofuran) through the dropping funnel kept at
-78° over a period of one hour. The mixture was then

allowed to stir for another three hours at -78° and brought

97

to room temperature, and left to be stirred overnight.

The solution was poured over 200 m1 of ice water and 600

ml ether. The ether layer was separated, and the aqueous

layer was extracted with another A00 m1 ether. The organic

extracts were combined, washed with 200 ml ice water, and
dried over anhydrous sodium sulfate. Solvent was removed
on a rotary evaporator and the residue was submitted to
chromatography on 50 gr aluminum oxide with carbon tetra-
chloride elution. The first fraction was separated and
identified to be the unreacted compoundlllé. The column
was then eluted with chloroform to give another compound
as a yellow liquid. This compound was identified as com-
pound 88% (1.1 g, yield 30%). Ms (m/e, %): 192 (8), 155
(6), 143 (10), 129 (2“), 117 (100), 115 (90), 91 (85),

77 (52), ir (neat): 3100, 2900, 1650, 180 MHz proton nmr
(6, 00013): 2.39 (dd, J=9.0 and 7.5 Hz, 2H), 2.65-2.75
(m, 2H), 3.59 (bd, J=12.0 Hz, 1H), 5.A7 (m, 1H), 5.5-5.95

(m, 6H), 6.05 (m, 1H), proton decoupled 13C nmr (6, CD013):

134.1 (10), 132.3 (lc), 129.6 (1c), 128.9 (1c), 126.0 (1c),

120.9 (10), 120.7 (10), 119.0 (10), 54.5 (1c), MH.O (lo),
u1.9 (1c), and 31.7 (1c). Partially proton decoupled C

nmr showed three doublets at 5A.5, AA.0, Al.9 and a triplet

at 31.7 ppm.

98

Attempts to Prepare 3-Chlorocyclopropene

A. UsingpSodium Amide

 

Into a 100 ml round bottomed three necked flask equipped
with magnetic stirrer, dropping funnel, nitrogen inlet was
placed A.0 g (0.1 mol) commercial sodium amide in 20 m1
mineral oil. The flask was heated to 60°, and a solution of
11.1 g (0.1 mol ) of 1,3-dichloropropene in 10 ml mineral
oil was added dropwise through the dropping funnel over a
period of one hour. The mixture was then heated to 80°
and kept at that temperature for another one hour. The
mixture was cooled to room temperature and the volatiles
were distilled into a trap kept in liquid nitrogen using
a high vacuum pump. Proton nmr spectrum of the volatile
material showed it to be the starting material, 1,3-dichloro-

propene;

B. Using Potassium t-Butoxide

 

1.7 g (0.015 mol) of 1,3-dichloropropene in 10 m1
ether was added dropwise to a rapidly stirring solution of
6.9 g (0.06 mol) of potassium t-butoxide in 15 m1 ether at
-10° over a period of one hour. The mixture was warmed to
room temperature and allowed to stir for another six hours.
The mixture was then filtered and the filtrate was concen-
trated at -30° using a high vacuum pump. The nmr spectrum

of the residue was quite messy and did not show the peaks

belonging to 3-chlorocyclopropene.

99

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