The first chiral zirconium(IV) catalyst for highly stereoselective sulfoxidation

Partially-hydrolized chiral Zr(IV) catalysts, based on C3 symmetric trialkanolamine ligands 1a-c in the presence of cumyl hydroperoxide, provide a new homogeneous system for the enantioselective sulfoxidation of a wide range of aryl alkyl sulfides. Ee’s in the range 80-90% are obtained, through the cooperative effect of two independent stereoselective processes, namely the direct asymmetric oxidation of the sulfide to the sulfoxide and its subsequent kinetic resolution to sulfone, allowing the recover of the desired product with yields up to 35%. In every reaction the peroxide is converted quantitatively with as little as 2% of catalyst