Chiral amides via copper-catalysed enantioselective conjugate addition
Abstract
A highly enantioselective one pot procedure for the synthesis of β-substituted amides was developed starting from the corresponding α,β-unsaturated esters. This new methodology is based on the copper-catalysed enantioselective conjugate addition of Grignard reagents to α,β-unsaturated esters and subsequent direct formation of amides by quenching the corresponding enolates with different amines. Various primary and secondary amines bearing alkyl or aryl substituents can be used giving rise to a large variety of β-substituted amides with excellent enantioselectivities.