Sulfoxide compounds are important synthetic intermediates, 1 and a wide range of methods for the selective oxidation of sulfides to sulfoxides have been developed for this transformation. 2 For example, aqueous hydrogen peroxide, 3 peracetic acid, 4 mCPBA, 5 sodium metaperiodate, 6 nitrogen tetraoxide, 7 and halogens 8 and their derivatives 8 have all been used as oxidants. Among them, aqueous 30% hydrogen peroxide is a particularly ...