Asymmetric oxidation of sulphides to sulphoxides catalysed by titanium complexes of N-salicylidene-L-amino acids

Oxidation of alkyl aryl and heterocyclic sulphides with ButOOH and a catalytic amount of titanium N-salicylidene-L-amino acids (0.1 mol equiv.) affords the corresponding sulphoxides with an enantiomeric excess (e.e.) up to 21%. The use of other metal complexes with the same ligands led to racemic products.