Metal-free chemoselective oxidation of sulfides by in situ generated Koser’s reagent in aqueous media

Selective oxidation of sulfides was successfully performed by employing phenyliodine diacetate as an oxidant with the catalysis of TsOH in aqueous solution under mild conditions. Sulfoxides were formed with 1.1 equiv of PhI(OAc)2 at room temperature; whereas sulfones were obtained in the presence of 2.1 equiv of PhI(OAc)2 at 80 °C under otherwise identical conditions. Notably, various sulfides were converted to corresponding sulfoxides or sulfones in good to high yields by this metal-free protocol.