Design of chiral bifunctional quaternary phosphonium bromide catalysts possessing an amide moiety.

ABSTRACT

Novel bifunctional quaternary phosphonium bromides possessing an amide moiety were designed for the highly enantioselective sulfenylation and chlorination of ß-ketoesters under base-free phase-transfer conditions. The tuning of an amide moiety of the catalyst was crucial to achieve high reactivity and enantioselectivity.