MECHANISM OF DECOMPOSITION OF 5,5-DIARYL-N-NITROSO-2-OXAZOLIDONES

Abstract

A migration aptitude study has been made of the alkaline decomposition of 5,5-diaryl-N-nitroso-2-oxazolidone to diarylacetylene with the aim of shedding light on the mechanism of the rearrangement step of the reaction. 5-Phenyl-5-p-trifluoromethylphenyl-N-nitroso- 14 2-oxazolidone-5-C was synthesized and converted to p-trifluoromethyl- 14 tolane-C , which was oxidized to benzoic acid and p-trifluoromethylbenzoic acid. The ratio of specific activities of the two acids was found to be 1:2, showing that the migration tendency of the phenyl group is twice that of the p-trifluoromethylphenyl group. This result has been interpreted in terms of an electronically-controlled migration step involving as an intermediate either a vinyl carbonium ion or a vinyl carbene.