Asymmetric Bromolactonization Catalyzed by a <i>C</i>₃‐Symmetric Chiral Trisimidazoline

Abstract

A productive alliance: In an enantioselective organocatalytic bromolactonization of 5-substituted hex-5-enoic acids (see scheme), it appears that the formation of an ion pair through interaction of the trisimidazoline catalyst 1 with the substrate both creates a chiral environment and promotes the cyclization by activating the carboxylic acid. DBDMH=1,3-dibromo-5,5-dimethylhydantoin.