Selective synthesis of sulfoxides and sulfones by methyltrioxorhenium-catalyzed oxidation of sulfides with hydrogen peroxide

Methyltrioxorhenium-catalyzed oxidation of sulfides with hydrogen peroxide in ethanol has been found to be an efficient catalytic system for the selective formation of sulfoxides and sulfones. The oxidation using an equimolar amount of hydrogen peroxide afforded sulfoxides in excellent yield, and the use of two molar amounts of hydrogen peroxide gave sulfones quantitatively. Strongly deactivated sulfide, bis(4-nitrophenyl) sulfide, was converted smoothly to the corresponding sulfoxide and sulfone in excellent yields. The functional group in the side chain of sulfide such as a carbon-carbon double bond was not affected under the reaction conditions, and the sulfur atom was selectively oxidized.