PHOTOREARRANGEMENT OF BICYCLO[2.2.1]HEPTENE-2-CARBONITRILE
.
THE OBSERVATION OP 1,2.AND 1,3-SIGMATROPIC SHIFTS-
by
~ Susan Vaitekunas. B.Sc.
\
~
A Thesi~
Submitted to the School of Graduate Studies in
Partial Fulfullment of the Requirement for the
Degree
.
Master of Science
McMaster University
November, 1981
PHOTOREARRANGEMENT OF BICYCLO[2.2.1]HEPTENE-2-CARBONITRILE
THE -OBSERVATION OF 1,2 AND
1,3-SIG~~TROPIC
l
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o
SHIFTS
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to my parents
.
Master of Science (1981)
(Chem~ stry)
TITLf:
,
McMaster Un;ver$i~y
Hamilton, Ontario
.
Photorearrangement of Bicyclo[2.2.1)heptene-2-carbanitrile
Observation of 1,2 and 1,3-S1gmatropic Shifts
\
AUTHOR:
.
Susan Vaitekunas, B.Sc. (Concordia University, Montreal, Quebec)
SUPERVISOR:
Dr. J.J. McCullough
\:)
NUMBER OF -P~GES:'
xiii, 106
)
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•
ABST-RACT
The
~,e-unsaturated
bi~yclo[2.2.1]heptene-2-carbonitril~,I,
nitrile,
was synthesized from norcamphor.
Irradiation in hexane with unfiltered
light from a medium pressure mercury arc lamp resulted in its conversion
.
to two products,
bicyclo[4.1.0]hept-2-ene-l-carbonitr,il~,
11, and tricyclo-
[4.1.0.0.3,71heptane-7-carbonitrile, III, in a 20:1 ratio.
/1
hv
~CN-' -h-e.x-a-ne~)
III
I
The structure-of the major rearrangement product, II, was proven by .
X-ray crystallography of its crystalline derivative, 1-methylamino-bicyclo-.
[4.1.0] hept-2-ene-p-bromobenzenesul fonate.
The m!nor product, III, was identi-
~
fied by catalytic hydrogenation to 7-cyanobicyclo[2.2.1]heptane and vpc comparison with authentic 7-cyanobicyclo[2.2.1]heptane synthesized from bicyclo[2.2.1]heptane-7-carboxylic acid.
The photorearrangement of I to II and III are orbital symmetry-allowed
photochemical 1,3 and 1,2-sigmatropic shifts, respectively. The 1,3-sigmatropic
shift has not been previously,observed in the photochemistry of a,a-unsaturated
nitriles while the 1,2 shift was observed in,the photorearrangement of
1-cyanocyclohexenes.
Further experiments are needed to determine whether or
not the rearrangements are concerted or diradical in nature.
Preliminary experiments on the related compound, bicyclo[3.2.0]oct-2ene-3-carbonjtrile, IV, synthesized from norbornene,indicate that it probably
undergoes the same type of rearrangements as I. The ratio for 1,3,to 1,2
a bond shifts seems to be 3:2 in this case.-
d:>-CN
IV
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ACKNOWLEDGEMENTS
,
I would like to
t~ank
my supervisor, Dr. J.J. McCullough for his
help, advice, and encouragement in this research.
express my
gratitud~
I would also like to
to Keith MacInnis for his suggestions and support.
Thank you to Dr. C.J.L. Lock and R. Faggiani for the crystal structure
•
I
determination, to F.A. Ramelan who obtained ,the mass spectra, to B. Sayers
for running the 13C nmr spectra, to Dr. J. Warkentin who supplied the sample
of bicyclo[2.2.1]heptane-l-carboxylic acid, and to Mrs. Gayle Griffin who
,
typed this thesis.
Finally I would like to offer my sincere thanks ,to the National
Science and Engineering
Research Council and McMaster University who
,
provided me with financial assistance.
I
j
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i
TABLE OF CONTENTS
Page
ABSTRACT
;i
ACKNOWLEDGEMENTS
iii
TABLE OF CONTENTS
iv
LIST OF FIGURES
viii
LIST Of" TABLES
ix
LIST',OF SCHEMES
x
ABBREVIATIONS
xi
I
INTRODUCTION
1
A.
Organic Photochemistry
1
B.
Pericyclic Reactions
4
(i)
Exocyclic Reactions
4
(ii)
Cycloaddition Reactions
'6
(ift) Sigmatropic Rearrangements
C.
7
Olefin Solution Photochemistry
10
(i)
General Comments
10 .,
(ii)
Cis-Trans Isomerization
11
(iii) Dimerization-[2+2]Cycloaddition
13
(iv)
16
Direct and Sensit5zed Irradiation of Cycloalkenes
in Hydroxylic Solvents
D.
II
(v)
Carbene Intermediates
22
(vi)
Reactions Involving lt3-H Shifts
32
Photochemistry of a,B-Unsaturated Nitriles
RESULTS
A.
42
Synthesis of
(i)
35
Bicyclo[2.2.1]Heptene-2-carbon~trile(135}
Conversion of Norcamphor (136) to 2,2-dichlorobicytl0
iv
42
42
Table of Contents continued
(2.2.1Jheptane (137)
(ii)
Dehydrohalogenation of 2t 2-dichlorobicycloI2.2.1Jheptane
42
(137)
(iii) Conversion of 2-Ghlprobicyclo{2.2.1Jheptene (11[) to
.Bicyclo(2.2.1Jhepterie-2-carbo~itrile
.•
44
(135)
•
B.
Irradiation of Bicyclo[2.2.1Jheptene-2-carbonitrile (135)
46
C.
Identification of the Major Rearrangement Product from Irradia-
47
-
tion of Bicyclo[2.2.1]heptene-2-carbonitrile. (135)
.
(~)
Synthesis of Bicyclo[4.1.0]heptane-1-carbonitrile (liL)
50
(ii) Attempts to Hydrogenate the Major Photorearrangement
53
Product from Irradiation of 135
,
(iii) Permanganate Oxidation of the Major Rearrangement Product
55
(iv) Attempts to Detenmine Presence of Bicyclo[3.2.1Jhept-2-
56
ene Carbon Skeleton by Pyrolysis
(v)
Attempted
Synthesi~
of Bicyclo[3.2.0Jheptane-l·Carbonitrile 58
Table of Contents continued
.'
acid (181) to Bicyclo[3.2.0]heptane-l-carbonitrile (175)
O.
The Crystal Structure of I-Methylaminobicyclo[4.1.0}hept-2-ene-
67
brosylate (193)
E.
Identificatio~
of Minor Photo product From Irradiation of
71-
Bicyclo[2.2.1]heptene-2-carbonitrile (135)
F.
Synthesis and Irradiation of Bicyclo[3.2.0]oct-2-ene-3-carboni-
73
tril e (197)
(i)
Formation of 3,4-Dibromobicyclo[3.2.1]oct-2-ene (198) by
74
Addition of Dibromocarbene to Norbornene Y22}
(ii) 'Allylic Reduction of 3,4-0ibromobicyclo[3.2.0]oct-2-ene
'75
(198)
(iii) Conversion of 3-Bromobicyclo[3.2.0]oct-2-ene (199) to
75
Bicyclo[3.2.0]oct-2-ene-3-carbonitrile (197)
{iv}
Exploratory Photolysis of Bicyclo[3.2.0]oct-2-ene-3-
76
carbonitrile (197)
III' EXPERIMENTAL
79
Materials
79
Instruments
79
A.
Synthesis of Bicyclo[2.2.1]heptene-2-carbonitrile (135)
80
(i)
Norcamphor (136)
80
(ii)
Dehydrohalogenation of 2,2-0ibromobicyclo[2.2.1}heptane
(137) to
+
2,2-0ichlorobicyclo[2.2.1]heptane.(137)
2-Chlorobicyclo[2.2.1Jhepten~
80
(138)
(iii) Conversion of 2-Chlorob1cyclo[2.2.1]hePtene (138) to
81
Bicyclo[2.2.1)heptene-2-carbonitrile (135)
B.
Irradiation of Bicyclo[2.2.1]heptene-2-carbonitrile (135)
82
C.
Synthesis of Bicyclo[4.1.0)heptane-l-carbonitrile (liL)
83
.
Table of Contents continued
(i)
Synthesis of
1-Cyanocycl~hexene (~)
83
(i i). Preparation of Trimethyl oxosul foxoni um Iodi de (148)
(iii) Generation of Dimethyloxosulfonium methyl ide
(~)
84
and
84
r.
Re~ction with l-cyanocyclohexene
D.
,I
(i29)
Synthesis of Bicyclo[3.2.0)heptane-1-carbonitrile (175)
-,
(i) Conversion of 1,3,5~Cycloheptatriene (178) to 1,3-
86
I
}
86
\
I
Cycloheptadiene-t-carboxylic acid (179)
(i i)
I
Photochemical Isomerization of 1,3-Cycloheptadiene-1-
87
carboxylic acid to Bicyclo[3.2.0]hept-6-ene-1-carboxylic·
acid (180)
(iii) Hydrogenation of Bicyclo[3.2.0)hept-6-ene-1-carboxylic
87
acid (180)
(iv)
Conver-sion of
Bicycl~[3.2.0)heptane-1-carboxylic acid
88
(181) to Bicyclo[3.2.0)heptane-l-carbonitrile (175)
E.
Preparation of Bicyclo[4.1.0)hept-2-ene-1-carbonitrile Deriva-
89
tive For X-Ray Work
(i)
Reduction of Bicyclo[4.1.0)hept-2-ene-l-carbonitrile (148)
89
(ii)
Preparation of I-Methylaminobicyclo[4.1.0)hept-2-ene
90
Brosyl ate (ill)
F.
Identification of Minor Rearrangement Product from Irradiation
90
of Bicyclo[2.2.1)heptene-l-carbonitrile (135)
(i)
Hydrogenation of 7-Cyanotricyclo[4.1:0.0 3 ,7)heptane
90
(ii)
Synthesis of 7-Cyanobicyclo[2.2.1]heptane (195) from
91
-
Bicyclo[2.2.1)heptane-7-carboxylic acid (196)
I
G.
Synthesis of Bicyclo[3.2.11oct-2-ene-3-carbonitrile (197)
92
Addition of Dibromocarbene to Norbornene (22)
92
(i)
.,
vii
-'.
Table of Contents continued
(ii)
The Reduction of 3t4-Dibromobicyclo[3.2.1}oct-2~ene(198)
92
to 3-Bromobicyclo[3.2.11oct-2-ene (1.22.).
(iii) Conversion of 3-Bromobicyclo[3.2.11oct-2-ene
(~~)
to
- 93
"
Bicyclo(3.2.1]oct-2-ene-3-carbonitrile (197)
H.
Exploratory Photolysis of
B;cyclo[3.2.1]oct'~-ene-3-carbonitrile
,
94
(197)
IV
CONCLUSION
95
References
104
/
I
viii
I
I
LIST OF FIGURES
Page
Figure 1.
Crystal Structure of I-methylaminobicyclo[4.1.0]hept-2-
68
ene brosylate (121)
Figure 2.
Crystal packing of 1-methylaminobicyclo[4.1.0]hept-2-ene
68
brosylate (193)
Figure 3.
Molecular Orbits Involved in Competing 1,2 and 1,3-Sigmatropic Shifts in Bicyclo[2.2.1]heptene-2-carbonitrile
99
LIST OF TABLES
Page
Rules for Symmetry.Allowed Electrocyclic Reactions
6
Rules for Symmetry-Allowed Cycloaddition Reaction
7
"
Rules for Symmetry-Allowed Sigmatropic Rearrangements
10
o
Selected Interatomic Distances (A) and Angles (deg.)
Table 1.
69
of I-methylaminobicyclo[4.1.0]hept-2-ene brosylate (193)
Best Planes (193)
Table 2.
j
...
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I
1
LIST OF SCHEMES
~
I
Rearrangement of 2,2,5,5-tetradeuterocyclohexene (Intermediate
28
70)
II
Rearrangement of
2,2,5,5-tetradeuter~cyclohexene
(Intermediate
29
Rearrangement of 2,2,5,5-tetradeuterocyclohexene (Intermediate
29
11)
III
]1) .
IV
Synthesis of Bicyclo[2.2.1]Heptene-2-carbonitrile (135)
4Z
V
Synthesis of the Methyl Esters of 1-Cyanocyclobutane-1,2-dicar-
56
boxylic acid (160) and Cyclobutane-1,1,Z-tricarboxylic acid (161)
VI
Synthesis of Bicyclo[3.2.0]heptane-1-carbonitrile
VII Attempted
Conver~ion
60
of 1,3-cycloheptadiene-1-carboxylic acid (179) 62
to 1,3-cycloheptadiene-1-carbonitrile (184)
VIII Mechanism for Conversion of Carboxylic Acids to Nitriles by
·65
Chlorosulfonyl Isocyanate
IX
Synthesis of p-bromosulfonamide of Bicyclo[4.1.0]hept-2-ene-l-
67
carbonitrile (143)
X
Identification of Tricyclo[4.1.0.0 3 ,7]heptane-7-carbonitrile (194)
72
XI
Synthesis of Bicyclo[3.2.1]oct-2-ene-3-carbonitrile (197)
74
XII Reartangements of Bicyclo[2:2.1]heptene-2-carbonitrile eill}
95
via 1,3-Sigmatropic Shifts
XI II Rearrangement of Bicyclo[2.2.1]heptene-2-carbonitrile (..ill.) by
96
1,3-shift (diradical mechanism)
XIV Rearrangement of
bicyclo[2.2.1]hepten~-2-carbonitrile(..ill.)
98
via 1,2-Shift
XV
Photorearrangement of Bicyclo[3.2.1loct-2-ene-3-carbonitrile (197) 101
xi
I,
r
LIST OF ABBREVIATIONS
o
A
angstrom
atm
atmosphere
bp
boil ing point
C
celsius
aibromocarbene
em
centimeter,
em -1
reciprocal centimeters
CSI
chlorosulfonyl isocyanate
d
doublet
deg
degrees
DMF
dimethylformamide
OMSO
dimethylsulfoxide
diethyl ether
electron volt
g
gas
g
gram
H-
hydrogen atom
hv
light
Hz
hertz
• IR
infrared
ISC
intersystem crossing
J
coupling constant
kcal
kilocalorie
kinetic hydrogen 'isotope effect
potassium tert-butoxide
1
1iter
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xii