Evidence for a Stereospecific 1,2-Elimination Reaction in a 1,1-Diazene. Synthesis and Decomposition of [N-Phenyl-(Threo-(and Erythro)-2-Deuterio-1-Methylpropl)Amino]Nitrene

Citation

Duan, Daniel C. (1983) Evidence for a Stereospecific 1,2-Elimination Reaction in a 1,1-Diazene. Synthesis and Decomposition of [N-Phenyl-(Threo-(and Erythro)-2-Deuterio-1-Methylpropl)Amino]Nitrene. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/zbfn-1t36. https://resolver.caltech.edu/CaltechTHESIS:09032019-103344869

Abstract

CHAPTER 1:

The mechanism of the formal 1,2-elimination reaction of 1,1-diazenes to alkenes is examined. 'fue syntheses and decomposition of [N-phenyl-(1-methylpropyl)amino]nitrene (6), [N-phenyl(erythro-2-deuterio-1-methylpropyl)amino]nitrene (7) and [N-phenyl-(threo-2-deuterio-1-methylpropyl)amino]nitrene (8) are reported. Oxidation of 1-(1-methylpropyl)-1-phenylhydrazine (9) with nickel peroxide at 100°C affords 1-butene, trans-2-butene, cis-2-butene, butane and benzene in ratios of 0.59:0.30:0.097:0.005:1.00. Reaction of the corresponding benzenesulfonamide 10 with base at 100°C affords similar ratios. Oxidation of 1-(erythro-2-deuterio-1-methylpropyl)-1-phenylhydrazine (14) at 100°C affords 1-butene, trans-2-butene (100±2% d₁) and cis-2-butene (2.8±2% d₁), and butane in ratios of 0.67:0.30:0.03:0.004. Oxidation of 1-(threo-2-deuterio-1-methylpropyl)-1-phenylhydrazine (20) at 100°C affords 1-butene, trans-2-butene (1.8±2% d₁) and cis-2-butene (97.9±2% d₁) and butane in ratios of 0.77:0.11:0.11:0.009. Reaction of the corresponding benzenesulfonamides 15 and 21 with base at 100°C affords similar results. Primary kinetic isotope effects for 2-butene formation from the erythro and threo 1,1-diazene diastereomers were 3.5 and 3.4, respectively. The 1,1-diazene 1,2-elimination reaction studied here is a stereospecific cis elimination process.

CHAPTER 2:

An attempt was made to observe chiral induction in a gas phase IR multiphoton photolysis using a circularly polarized output from a TEA CO₂ laser. The molecule studied was trans-1,2-divinylcyclobutane (1) in the gas phase at 0.6 torr. Racemic samples were photolyzed at 977 cm^-1 (=CHR bending) with 75 focused (0.8-0.9J) pulses. This resulted in about 33% conversion to 1,3-butadiene (2), 4-vinylcyclohexene (3) and 1.5-cyclooctadiene (4). A large number of samples were combined and the 1 (44mg) and 3 (6mg) were isolated by VPC. Neither showed optical activity.

CHAPTER 3:

The possibility that triazolenitrenes (2) are involved in the photodecomposition of s-tetrazines (1) is considered. It was found that oxidation of 1-amino-2,5-diphenyl-1,3,4-triazole (5) in the presence of tetramethylethylene gave a high yield of triazolenitrene trapping product 6. Photolysis of 3,6-diphenyl-1,2,4,5-tetrazine (4) under these conditions failed to yield the adduct 6. Unsuccessful attempts were also made to prepare (2,5-di-tert-butyl-1,3,4-triazolidyl)nitrene (7) as a persistent species at low temperatures.

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