Oxidation of Sulfides with Hydrogen Peroxide Catalyzed by Vitamin B2 Derivatives

5-Ethyl-3-methyl-2,4:3,5-di-O-methylenedioxyriboflavinium perchlorate (1, DMRFlEt(+)ClO(4) (-)), derived readily from commercially available vitamin B-2 (riboflavin), exhibits high catalytic activity for the oxidation of organic sulfides with hydrogen peroxide. The reaction provides an efficient and selective method for the oxidative transformation of organic sulfides to the corresponding sulfoxides under mild conditions. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications (R) for the following free supplemental resource: Full experimental and spectral details.]