Hypervalent iodine(V)-induced asymmetric oxidation of sulfides to sulfoxides mediated by reversed micelles: Novel nonmetallic catalytic system

Although several types of chiral hypervalent iodine reagents have been used for asymmetric induction, all of them have needed more than a stoichiometr ic amount of chiral reagents and have shown low enantioselectivities. The d escribed new catalytic asymmetric oxidation using a hypervalent iodine(V) r eagent, iodoxybenzene (PhIO2), in a cationic reversed micellar system provi des the first example of a catalytic asymmetric oxidation of sulfides to su lfoxides in high chemical yield with moderate to good enantioselectivity wi thout the use of any transition-metal catalysts. The solubilization and act ivation of PhIO2 by adding catalytic amounts of both cetyltrimethylammonium bromide (CTAB) and a chiral tartaric acid derivative were found to be indi spensable for the enhancement of chemical and optical yields.