On the mechanism of titanium-tartrate catalyzed asymmetric epoxidation

Abstract

The experimental rate equation for titanium-tartrate catalyzed asymmetric epoxidation by tertbutyl hydroperoxide is reported. The catalyst is a dimer, and a structure of C2 symmetry is proposed. The mechanism of the reaction is discussed with respect to kinetic resolution of racemic secondary allylic alcohols as well as the enantioselectivity of epoxidation of prochiral substrates. The alignment of a lone pair of the reactive alkyl peroxo-oxygen atom with the olefin Π orbital is postulated as an important interaction in the transition state. © 1983 IUPAC