A highly efficient and selective oxidation of sulfides to sulfones with periodic acid catalyzed by CrO3 is described. A variety of electron-rich and electron-deficient sulfides were oxidized to sulfones with 2 mol% CrO3 in acetonitrile at room temperature in excellent yields. Sulfides with other readily oxidized functional groups were selectively oxidized to sulfones in high yields with 10 mol% CrO3 in ethyl acetate/acetonitrile at-35° C.
