KF adsorbed on alumina effectively promotes the epoxidation of electron deficient alkenes by anhydrous t-BuOOH

Abstract

KF adsorbed on alumina (KF-Al₂O₃) has been studied in detail for the epoxidation of electron deficient alkenes with anhydrous t-BuOOH. Aqueous base sensitive functional groups survive the reagent. Cyclopentenones are oxidized in decent to quantitative yields without showing any observable aldol products. α,β,γ,δ-Dienones are regioselectively oxidized at the α,β-position. Unlike aqueous alkaline H₂O₂, KF-Al₂O₃ is non-stereospecific and offers a mixture of cis and trans oxides from most acyclic enones. Except for the oxidation of α,β-unsaturated lactones and for the difference in reaction rates, the present reagent is, in general, similar to the t-BuOOH-DBU combination.