Nucleophilic epoxidation of γ-hydroxyvinyl sulfoxide derivatives

The nucleophilic epoxidation of simple (y-silyloxy)vinyl sulfoxides takes place with complete stereocontrol and high yields. For substrates bearing an additional substituent at the y position, a reinforcing/nonreinforcing scenario is operative. While E and Z silylated substrates undergo a primarily sulfur directed epoxidation with good to excellent diastereocontrol, the related (E)-(2-methoxyethoxy)methyl ethers display diminished selectivity for the diastereomer derived from the nonreinforcing scenario.