Functionalization of α,β-unsaturated esters and ketones:: A facile and highly stereoselective one-pot approach to N-protected α,β-dehydroamino acid derivatives

A new, facile, and highly stereoselective protocol toward alpha,beta-dehydroamino acid derivatives has been developed. The one-pot synthesis was very convenient to perform by using the aminohalogenation reaction of alpha,beta-unsaturated esters and ketones followed by treatment with specific bases. Only two [2.2.2] bicyclic organic bases were found to be effective for this transformation. Good yields (58-68%) and excellent Z-selectivity were obtained for 12 examples.