Catalytic Epoxidation of Alkenes with Oxone

Article abstract of DOI:10.1021/jo00110a049

A practical, general and efficient protocol for the catalytic epoxidation of alkenes has been developed.The in situ generation of reactive dioxiranes capable of epoxidizing a variety of alkenes under biphasic conditions has been accomplished using phase transfer catalysts bearing a carbonyl group.Optimal epoxidation conditions employ 10 mol percent of 1-dodecyl-1-methyl-4-oxopiperidinium triflate (8d(+)OTf(-)) in a CH2Cl2/pH 7.5-8.0 biphase using potassium monoperoxosulfate (Oxone) as the oxidant.Optimization of the conditions identified (1) slow addition rate, (2) pH 7.5-8.0, (3) N-dodecyl chain, and (4) the triflate salt as key experimental and structural variables.A selection of nine olefins was successfully oxidized to the corresponding epoxides in 83-96percent yield.