Highly enantioselective epoxidation catalyzed by cinchona thioureas: synthesis of functionalized terminal epoxides bearing a quaternary stereogenic center.

A brilliant debut! Cinchona thioureas have been reported for the first time as catalysts in the area of asymmetric oxidations. They efficiently promote an unprecedented highly enantioselective epoxidation of deactivated 1,1-disubstituted alkenes to terminal epoxides containing a quaternary stereogenic center (see scheme).