Asymmetric epoxidation of 2-arylidene-1,3-diketones: facile access to synthetically useful epoxides

Abstract

In this article the first enantioselective epoxidation reaction of acyclic and cyclic 2-arylidene-1,3-diketones is reported. Easily accessible or commercially available α,α-diaryl prolinols as the organocatalysts in the presence of tert-butyl hydroperoxide (TBHP) provide the corresponding epoxides in high to excellent yield (up to 99%) and up to 85% ee (ee >90% after crystallisation). These epoxides are pharmaceutically important building blocks and intermediates for the synthesis of densely functionalised epoxide derivatives.