Oxidative esterification, thioesterification, and amidation of aldehydes by a two-component organocatalyst system using a chiral N-heterocyclic carbene and redox-active riboflavin

摘要

Flavin of the month! Triazolium-derived N-heterocyclic carbenes (NHCs) and a flavin catalyzed the oxidative esterification, thioesterification, and amidation of aldehydes with various alcohols, thiols, and amines, respectively, with O_2 as the terminal oxidant (see scheme; R~1=aryl; R~2, R~3=alkyl or aryl). By using a chiral NHC catalyst, the enantioselective acylation promoted the kinetic resolution of racemic alcohols and the desymmetrization of a meso-diol.