PHOTOREARRANGEMENT OF BICYCLO[2.2.1]HEPTENE-2-CARBONITRILE
Transcript of PHOTOREARRANGEMENT OF BICYCLO[2.2.1]HEPTENE-2-CARBONITRILE
PHOTOREARRANGEMENT OF BICYCLO[2.2.1]HEPTENE-2-CARBONITRILE.
THE OBSERVATION OP 1,2.AND 1,3-SIGMATROPIC SHIFTS-
by
\~ Susan Vaitekunas. B.Sc.
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A Thesi~
Submitted to the School of Graduate Studies inPartial Fulfullment of the Requirement for the
Degree .Master of Science
McMaster UniversityNovember, 1981
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PHOTOREARRANGEMENT OF BICYCLO[2.2.1]HEPTENE-2-CARBONITRILE ~
THE -OBSERVATION OF 1,2 AND 1,3-SIG~~TROPIC SHIFTSl
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to my parents
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Master of Science (1981)(Chem~ stry)
McMaster Un;ver$i~y
Hamilton, Ontario,
.TITLf: 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
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NUMBER OF -P~GES:' xiii, 106
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•ABST-RACT
The ~,e-unsaturated nitrile, bi~yclo[2.2.1]heptene-2-carbonitril~,I,
was synthesized from norcamphor. Irradiation in hexane with unfiltered
light from a medium pressure mercury arc lamp resulted in its conversion
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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~)
I III
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 com-
parison 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-2
ene-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.-
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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. I would also like to
express my gratitud~ 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.
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ABSTRACT
ACKNOWLEDGEMENTS
TABLE OF CONTENTS
LIST OF FIGURES
LIST Of" TABLES
LIST',OF SCHEMES
ABBREVIATIONS
I INTRODUCTION
I I
TABLE OF CONTENTS
A. Organic Photochemistry
B. Pericyclic Reactions
(i) Exocyclic Reactions
(ii) Cycloaddition Reactions
(ift) Sigmatropic Rearrangements
C. Olefin Solution Photochemistry
(i) General Comments
(ii) Cis-Trans Isomerization
(iii) Dimerization-[2+2]Cycloaddition
(iv) Direct and Sensit5zed Irradiation of Cycloalkenes
in Hydroxylic Solvents
(v) Carbene Intermediates
(vi) Reactions Involving lt3-H Shifts
D. Photochemistry of a,B-Unsaturated Nitriles
RESULTS
A. Synthesis of Bicyclo[2.2.1]Heptene-2-carbon~trile(135}
(i) Conversion of Norcamphor (136) to 2,2-dichlorobicytl0
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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 44
.Bicyclo(2.2.1Jhepterie-2-carbo~itrile (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
brosylate (193)
E. Identificatio~ of Minor Photo product From Irradiation of
Bicyclo[2.2.1]heptene-2-carbonitrile (135)
F. Synthesis and Irradiation of Bicyclo[3.2.0]oct-2-ene-3-carboni-
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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) + 2,2-0ichlorobicyclo[2.2.1]heptane.(137) 80
(ii) Dehydrohalogenation of 2,2-0ibromobicyclo[2.2.1}heptane 80
(137) to 2-Chlorobicyclo[2.2.1Jhepten~ (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
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(i) Synthesis of 1-Cyanocycl~hexene (~) 83
(i i). Preparation of Trimethyl oxosul foxoni um Iodi de (148) 84
(iii) Generation of Dimethyloxosulfonium methyl ide (~) and 84
Re~ction with l-cyanocyclohexene (i29)
D. Synthesis of Bicyclo[3.2.0)heptane-1-carbonitrile (175)-,
(i) Conversion of 1,3,5~Cycloheptatriene (178) to 1,3
Cycloheptadiene-t-carboxylic acid (179)
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Photochemical Isomerization of 1,3-Cycloheptadiene-1-
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-carboxylicacid 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[4.1:0.03,7)heptane 90
(ii) Synthesis of 7-Cyanobicyclo[2.2.1]heptane (195) from 91
Bicyclo[2.2.1)heptane-7-carboxylic acid (196)-IG. Synthesis of Bicyclo[3.2.11oct-2-ene-3-carbonitrile (197) 92
(i) Addition of Dibromocarbene to Norbornene (22) 92
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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,
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(197)
IV CONCLUSION
References
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Figure 1.
Figure 2.
Figure 3.
LIST OF FIGURES
Crystal Structure of I-methylaminobicyclo[4.1.0]hept-2
ene brosylate (121)
Crystal packing of 1-methylaminobicyclo[4.1.0]hept-2-ene
brosylate (193)
Molecular Orbits Involved in Competing 1,2 and 1,3-Sigma
tropic Shifts in Bicyclo[2.2.1]heptene-2-carbonitrile
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LIST OF TABLES
Rules for Symmetry.Allowed Electrocyclic Reactions
Rules for Symmetry-Allowed Cycloaddition Reaction"
Rules for Symmetry-Allowed Sigmatropic Rearrangements
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Table 1.
Table 2.
oSelected Interatomic Distances (A) and Angles (deg.)
of I-methylaminobicyclo[4.1.0]hept-2-ene brosylate (193)
Best Planes (193)
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LIST OF SCHEMES
Rearrangement of 2,2,5,5-tetradeuterocyclohexene (Intermediate
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II Rearrangement of 2,2,5,5-tetradeuter~cyclohexene (Intermediate 29
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III Rearrangement of 2,2,5,5-tetradeuterocyclohexene (Intermediate 29
]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 60
VII Attempted Conver~ion 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[4.1.0.03 ,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
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A
atm
bp
C
em-1em
CSI
d
deg
DMF
OMSO
g
g
H-
hv
Hz
• IR
ISC
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kcal
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LIST OF ABBREVIATIONS
angstrom
atmosphere
boil ing point
celsius
aibromocarbene
centimeter,
reciprocal centimeters
chlorosulfonyl isocyanate
doublet
degrees
dimethylformamide
dimethylsulfoxide
diethyl ether
electron volt
gas
gram
hydrogen atom
light
hertz
infrared
intersystem crossing
coupling constant
kilocalorie
kinetic hydrogen 'isotope effect
potassium tert-butoxide
1iter
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