A highly enantioselective one-pot sulfur ylide epoxidation reaction

Enantiomerically pure tricyclic C2-symmetric sulfide 1 can be prepared in high yield and only three steps from d-mannitol. When used in a one-pot sulfur ylide mediated epoxidation reaction, between 94 and 98% enantiomeric excess was obtained; the highest reported to date for the catalytic process. Molecular modelling studies of the ylide conformation provides a basis for understanding the stereochemical outcome of the reaction.