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

摘要

Heteroaromatic sulfoxides, especially 1H-benzimidazolyl pyridinylmethyl 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 sulfoxides were obtained in high yield (97%) with excellent enantiomeric excess (tip to 98%). ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)