Asymmetric induction and configurational correlations in oxidations at sulphur. Part IV. Oxidation of aryl alkyl sulphoxides to sulphones by optically active peroxy-acids

Abstract

Oxidations of racemic aryl alkyl sulphoxides with 0·5 molar equivalents of optically active peroxy-acids SMLC·CO₃H afford mixtures of sulphones and optically active sulphoxides. The chirality of the sulphoxides depends on that of the peroxy-acids and on the nature of the alkyl group bonded to sulphur. Opposite stereospecificity is found in asymmetric oxidations of sulphoxides and of sulphides with the same peroxy-acid, that is to say the enantiomeric sulphoxides formed preferentially from the sulphides are found to be those oxidised more slowly to sulphones. Both asymmetric inductions can be interpreted with the same model, based on principles of steric control like those applied to asymmetric inductions at carbon.