Hypervalent Iodine(V)-Induced Asymmetric Oxidation of Sulfides to Sulfoxides Mediated by Reversed Micelles: Novel Nonmetallic Catalytic System

Abstract

Although several types of chiral hypervalent iodine reagents have been used for asymmetric induction, all of them have needed more than a stoichiometric amount of chiral reagents and have shown low enantioselectivities. The described new catalytic asymmetric oxidation using a hypervalent iodine(V) reagent, iodoxybenzene (PhIO(2)), in a cationic reversed micellar system provides the first example of a catalytic asymmetric oxidation of sulfides to sulfoxides in high chemical yield with moderate to good enantioselectivity without the use of any transition-metal catalysts. The solubilization and activation of PhIO(2) by adding catalytic amounts of both cetyltrimethylammonium bromide (CTAB) and a chiral tartaric acid derivative were found to be indispensable for the enhancement of chemical and optical yields.