Catalytic Enantioselective Silylation of N-Sulfonylimines: Asymmetric Synthesis of α-Amino Acids from CO2 via Stereospecific Carboxylation of α-Amino Si lanes

A catalytic enantioselective silylation of N-tertbutylsulfonylimines using a Cu secondary diamine complex was demonstrated. The resulting optically active alpha-amino silanes could be carboxylated under a CO2 atmosphere (1 atm) to afford the corresponding a-amino acids in a stereoretentive manner. This two-step sequence provides a new synthetic protocol for optically active a-amino acids from gaseous CO2 and imines in the presence of a catalytic amount of a chiral source.