Catalytic Asymmetric Oxidation of Heteroaromatic Sulfides with tert‐Butyl Hydroperoxide Catalyzed by a Titanium Complex with a New Chiral 1,2‐Diphenylethane‐1,2‐diol Ligand

Abstract

AbstractHeteroaromatic sulfoxides, especially 1H‐benzimidazolylpyridinylmethyl sulfoxides, usually used as the blockbuster gastric proton pump inhibitors (PPIs), have been prepared highly enantioselectivily by catalytic asymmetric oxidation of sulfides attached to nitrogen‐containing heterocyles with tert‐butyl hydroperoxide in the presence of a chiral titanium complex, formed in situ from Ti(iPrO)4, chiral 1,2‐diphenylethane‐1,2‐diol 3c and water. The chiral sufoxides were obtained in high yield (97 %) with excellent enantiomeric excess (up to 98 %). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)