Dioxirane Epoxidation of α,β‐Unsaturated Ketones

Abstract The synthesis of epoxides 3a – r is achieved in excellent yields by reaction of the α,β‐unsaturated ketones 1a–c, 4,4′‐disubstituted (E)‐chalcones 1d–o, and 2′‐hydroxy‐4‐substituted (E)‐chalcones 1p – r with isolated dimethyldioxirane (2a) (as acetone solution) and/or in situ generated ethyl(methyl)dioxirane (2b). This method constitutes a useful alternative to the Weitz‐Scheffer epoxidation (alkaline H2O2) of such electronpoor substrates.