Highly Enantioselective Epoxidation of 2,4‐Diarylenones by Using Dimeric Cinchona Phase‐Transfer Catalysts: Enhancement of Enantioselectivity by Surfactants

Abstract

Dramatic increases in reaction rates and enantioselectivities can be effected by the use of surfactants for the phase‐transfer catalytic epoxidation of aromatic enones. Based on the X‐ray crystal structure of the most effective catalyst—a modified cinchona alkaloid—a plausible transition state of the reaction has been modeled (see picture; HOO− yellow, C gray, H white, N blue, O red).