Tunable Cinchona-Based Thioureas-Catalysed Asymmetric Epoxidation to Synthetically Important Glycidic Ester Derivatives

A novel class of synthetically important glycidic esters has been obtained via an asymmetric epoxidation of trans-alpha-cyano-alpha, beta-unsaturated esters catalysed by a multifunctional Cinchona alkaloidderived thiourea/tert-butyl hydroperoxide (TBHP) system. The glycidic esters, isolated in excellent yield with complete trans-diastereocontrol and high enantioselectivity, proved to be versatile building blocks to access challenging small targets bearing a quaternary stereocenter.