Catalytic Enantioselective Oxidative Homocoupling of 2-Acyl Imidazoles

Abstract

A diastereoselective and enantioselective construction of 2,3-disubstituted 1,4-dicarbonyl compounds is reported. Nishiyama's RuPhebox complex (2.0 mol% catalyst loading) serves as a chiral Lewis acid catalyst in conjunction with BrCCl3 and a base for the oxidative homocoupling of 2-acyl imidazoles via the stereocontrolled reaction of intermediate Ru enolates with in situ brominated 2-acyl imidazoles. Cleavage of the achiral imidazole auxiliary provides optically active 2,3-disubstituted succinic acids which are useful intermediates in the synthesis of chiral compounds like the natural product class of lignans. (Figure presented.).