Simple protocol for enhanced (E)-selectivity in Julia–Kocienski reaction

A short and efficient Julia–Kocienski olefination protocol, based upon the use of chelating agents (18-crown-6 or TDA-1 for K+; 12-crown-4 or HMPA for Li+), was developed. This protocol enhances the (E)-selectivity of the reaction and the desired olefins are obtained generally with >10:1 (E/Z)-selectivity.