Catalytic route to the synthesis of optically active β,β-difluoroglutamic acid and β,β-difluoroproline derivatives

beta,beta-Difluorinated amino acid derivatives were synthesized via Mg(O)-promoted defluorination of alpha-trifluoromethyl iminoester. Bromination of the difluoroenamine afforded the bromodifluoromethyl iminoester in good yield. Pd-catalyzed asymmetric hydrogenation of the bromodifluoromethyl iminoester and the subsequent transformations provided optically active beta,beta-difluoroglutamic acid and difluoroproline derivatives.