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Carbene Rearrangements: Intramolecular Interaction of a Triple Bond with a Carbene Center

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Carbene Rearrangements: Intramolecular Interaction of a Triple Bond with a Carbene Center An Abstract OF THE THESIS OF Jose C. Danino for the degree of Doctor of Philosophy in Chemistry presented on _Dcc, Title: Carbene RearrangementE) Intramolecular Interaction of a Triple Bond with aCarbene Center Redacted for Privacy Abstract approved: Dr. Vetere. Freeman The tosylhydrazones of2-heptanone, 4,4-dimethy1-2- heptanone, 6-heptyn-2-one and 4,4-dimethy1-6-heptyn-2- one were synthesizedand decomposed under a varietyof reaction conditions:' drylithium and sodium salt pyrolyses, sodium methoxide thermolysesin diglyme and photolyses of the lithium salt intetrahydrofuran. The saturated ana- logues 2-heptanone tosylhydrazoneand its 4,4-dimethyl isomer afforded the alkenesarising from 6-hydrogeninser- product distribution in the tion. It was determined that differ- dry salt pyrolyses of2-heptanone tosylhydrazone was ent for the lithiumand the sodium salts. However, the product distribution of thedry sodium salt was verysimilar diglyme to product distributionobtained on thermolysis in explained by a with sodium methoxide. This difference was reaction of lithium bromide(present as an impurity inall compound to the lithium salts)with the intermediate diazo afford an organolithiumintermediate that behaves in a some- what different fashionthan the free carbene.The unsaturated analogues were found to produce a cyclic product in addition to the expected acyclic alkenes arising from 3-hydrogen insertion. By comparison of the acyclic alkene distri- bution obtained in the saturated analogues with those in the unsaturated analogues, it was concluded that at leastsome cyclization was occurring via addition of the diazo moiety to the triple bond. It was determined that the organo- lithium intermediateresulting from lithium bromide cat- alyzed decomposition of the diazo compound was incapable of cyclization. Alkene distribution upon pyrolyses of the lith- ium salt of 4,4-dimethy1-6-heptyn-2-one tosylhydrazone at differ- ent temperatures provides evidence for cyclization to beoccur- ring by a carbenic pathway in competition with the diazo pathway. Dry salt pyrolyses of 3,5,5-trimethy1-2-cyclohexenone tosylhydrazone showed that 1-carbena-3,5,5-trimethy1-2- cyclohexene does not open up to the acyclic carbene 2- carbena-4,4-dimethy1-6-hexyne. Direct photolysis of 1-diazo-5-hexyn-2-one afforded only the ketene arising from a Wolff rearrangement which was allowed to react with methanol to afford methyl 5- hexynoate before isolation. Sensitized photolysis afforded only the product arising from hydrogen abstraction by the triplet carbene: 5-hexyn-2-one. No cyclization products were detected under these reaction conditions. Carbene Rearrangements: Intramolecular Interaction of a Triple Bond With a Carbene Center by Jose C. Danino A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Commencement June 1983 APPROVED: Redacted for Privacy Professor of Chemistry in charge of major Redacted for Privacy Chairman of Department of Chemistry Redacted for Privacy ritDean of Gra to bcnool d Date thesis is presented Typed by Carolyn Barney for Jose C. DaRino To Dian, Ruth and Cucho for their love and encouragement ACKNOWLEDGEMENTS It is difficult to express with words the gratitude the author feels towards Professor Peter K. Freeman for his help, encouragement and patience during the preparation of this thesis. His personal friendship is and hopefully willcon- tinue to be a special asset of our scientific relationship. The faculty of the Chemistry Department are also thanked for their help, in particular Drs. Thies, White, Marvell and Gleicher. Thanks are also due to my fellow students for their friendship and helpful discussions, particularly K. Swenson, L. Bass, G. Moy and L. Hutchinson. The Chemistry Department is thanked for providing a teaching assistance- ship during most of my stay at OSU. The author wishes to acknowledge the support, both moral and financial, from his parents. And a very special grati- tude is extended to my wife Dian for her emotional and financial support during the writing of this thesis. TABLE OF CONTENTS CHAPTER 1. INTRODUCTION I. General Introduction 1 II. Formation of Carbenes 12 A. Decomposition of Diazo Compounds 12 B. Decomposition of Tosylhydrazones 14 C. Decomposition of Diazirines 18 D. Decomposition of Organomercury Compounds 19 E. Decomposition of Haloforms 21 III. Reactions of Carbenes 24 A. Insertion into Carbon Hydrogen Bonds 24 B. Addition to Carbon-Carbon Double and Triple Bonds 31 C. Carbene Rearrangements 40 1. 1,2-Shifts 41 2. Fragmentations 53 3. Rearrangements of Stabilized Carbenes 60 4. Carbene to Carbene Rearrangements 67 IV. a-Ketocarbenes 81 A. Synthesis of Diazoketones 81 1. Reaction of an Acid Chloride with Diazomethane 81 2. Oxidation of Ketohydrazones 85 3. Chloramine Oxidation of Ketoximes 87 4. Decomposition of a-Ketotosyl- hydrazones 87 5. Decomposition of Nitroso Compounds 89 6. Diazo Group Transfer 90 B. The Wolff Rearrangement 93 C. Carbene Reactions of Ketocarbenes 101 V. Research Objectives 103 CHAPTER 2. RESULTS AND DISCUSSION I. General 104 II. The Saturated Analogues: 2-Carbenaheptane and 2-Carbena-4,4-dimethylheptane 106 III. The 2-Carbena-6-heptyne and the 2-Carbena- 4,4-dimethylhexyne Systems 112 IV. The 1-Carbena-6-hexyn-2-one System 138 V. Conclusions 145 CHAPTER 3. EXPERIMENTAL SECTION General Methods 148 General Procedure for the Syntheses and Pyrolyses of the Tosylhydrazone Lithium Salts 149 General Procedure for the Syntheses and Pyrolyses of the Tosylhydrazone Sodium Salts 150 General Procedure for the Thermal Tosyl- hydrazone Decompositions with Sodium Methoxide in Diglyme 150 General Procedure for the Photolytic Decomposition of the Tosylhydrazone Lithium Salts 151 Synthesis of Tosylhydrazine 152 Synthesis of 4,4- Dimethyl -2- heptanone 153 Synthesis of 4,4-Dimethy1-2-heptanone Tosylhydrazone 154 Vacuum Pyrolysis of the Dry Lithium Salt of 4,4-Dimethy1-2-heptanone Tosylhydrazone.155 Thermal Decomposition of 4,4-Dimethy1-2- heptanone Tosylhydrazone with Sodium Methoxide in Diglyme 155 Photolytic Decomposition of the Lithium Salt of 4,4- Dimethyl -2- heptanone Tosyl- hydrazone 156 Stereochemical Integrity of the Alkene Products Derived from the Photochemical Decomposition of the Lithium Salt of 4,4- Dimethy1-2-heptanone Tosylhydrazone 156 Identification of Products from the De- composition of 4,4-Dimethy1-2-heptanone Tosylhydrazone 157 Synthesis of 2,3-Epoxy-3,5,5-Trimethyl- cyclohexanone 159 Synthesis of 4,4-Dimethy1-6-heptyn-2-one 161 Synthesis of 4,4-Dimethy1-6-heptyn-2-one Tosylhydrazone 162 Vacuum Pyrolyses of the Dry Lithium Salt of 4,4-Dimethy1-6-heptyn-2-one Tosyl- hydrazone 163 Vacuum Pyrolyses of the Dry Lithium Salt of 4,4-Dimethy1-6-heptyn-2-one Tosyl- hydrazone in the Presence of Unreacted Tosylhydrazone 164 Vacuum Pyrolyses of the Dry Sodium Salt of 4,4-Dimethy1-6-heptyn-2-one Tosyl- hydrazone 164 Vacuum Pyrolyses of the Dry Sodium Salt of 4,4-Dimethy1-6-heptyn-2-one Tosyl- hydrazone in the Presence of Lithium Bromide 165 Thermal Decomposition of 4,4-Dimethy1- 5-heptyn-2-one Tosylhydrazone with Sodium Methoxide in Diglyme 165 Photolytic Decomposition of the Lithium Salt of 4,4-Dimethy1-6-heptyn-2-one Tosylhydrazone 165 Chemical Confirmation of the Structureof the Lithium Salt of 4,4- Dimethyl -6-heptyn- 2 -one Tosylhydrazone 166 Identification of Products from the Reac- tions of 4,4-Dimethy1-6-heptyn-2-one Tosylhydrazone 166 Synthesis of 3,5,5-Trimethy1-2-cyclohexe- none Tosylhydrazone 169 Synthesis of 1,5,5-Trimethy1-1,3-cyclo- hexadiene NMR Decoupling Experimenton 1,5,5-Trimethy1-1,3-cyclohexadiene 170 Vacuum Pyrolyses of the Lithium Salt of 3,5,5-Trimethy1-2-cyclohexenone Tosyl- hydrazone 173 Vacuum Pyrolyses of the Dry Sodium Salt of 3,5,5-Trimethy1-2-cyclohexenone Tosylhydrazone 173 Vacuum Pyrolyses of the Dry Sodium Salt of 3,5,5-Trimethy1-2-cyclohexenone Tosylhydrazone in the Presence of Lithium Bromide 174 Thermal Stability of 1,5,5-Trimethy1-1,3- cyclohexadiene and 5,5-Dimethyl-l-methy- lene-2-cyclohexene 174 Chemical Confirmation of the Structure of the Lithium Salt of 3,5,5-Trimethy1- 2-cyclohexenone Tosylhydrazone 175 Identification of Products from the Decomposition of the Lithium Salt of 3,5,5-Trimethy1-2-cyclohexenone Tosyl- hydrazone 175 Synthesis of 2-Heptanol 176 Synthesis of Pyridinium Chlorochromate 178 Synthesis of 2-Heptanone 178 Synthesis of 2-Heptanone Tosylhydrazone 179 Vacuum Pyrolysis of the Dry Lithium Salt of 2-Heptanone Tosylhydrazone 180 Vacuum Pyrolysis of the Dry Sodium Salt of 2-Heptanone Tosylhydrazone 180 Thermal Decomposition of 2-Heptanone Tosylhydrazone. with Sodium Methoxide in Diglyme 181 Photolysis of the Lithium Salt of 2-Heptanone Tosylhydrazone 181 Identification of Products from the Decompositions of 2-Heptanone Tosylhydrazone 181 Synthesis of 1-Heptene 182 Synthesis of Pentyl Triphenylphosphonium Bromide 182 Synthesis of cis-2-Heptene 183 Synthesis of 6-Acety1-3-methy1-2- cyclohexenone 184 Synthesis of 3-Methyl -2-cyclohexenone 184 Synthesis of 2,3-Exposy-3-methylcyclo- hexanone 185 Synthesis of 6-Heptyn-2-one 186 Synthesis of 6-Heptyn-2-one Tosyihydrazone 187 Vacuum Pyrolyses of the Dry Lithium Salt of 6-Heptyn-2-one Tosyihydrazone 188 Vacuum Pyrolyses of the Dry Sodium Salt of 6-Heptyn-2-one Tosylhydrazone 189 Photolysis of the Lithium Salt of 6- Heptyn-2-one Tosylhydrazone 189 Identification of Products from the Reactions of 6-Heptyn-2-one Tosyihydrazone 189 Synthesis of 3- Methyl -2- cyclohexenone Tosyihydrazone 191 Synthesis of 1-Methyl-1,3-cyclohexadiene
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