Thermolysis of Δ 3 -1,3,4-oxadiazolin-2-ones and 2-phenylimino-Δ 3 -1,3,4-oxadazolines derived from α,β-epoxyketones. An alternative method for the convers of α,β-epoxyketones to alkynones and alkynals

Abstract

Thermolyses in polar solvents, of Δ 3 -1,3,4-oxadiazolin-2-ones or 2-phenylimino-Δ 3 -1,3,4-oxadiazolines derived from α,β-epoxyketones, yields acetylenic carbonyl compounds. Good yields of acetylenic aldehydes and ketones are obtained for those cases in which the epoxide is ring fused. Extension to acyclic cases failed primarily due to predominance of a parallel decomposition pathway. The method complements the procedures developed by Eschenmoser and co-workers for the conversion of, α,β-epoxyketones into acetylenic carbonyl compounds.