Asymmetric synthesis of functionalized tetrasubstituted α-aminophosphonates through enantioselective aza-Henry reaction of phosphorylated ketimines

Bifunctional Cinchona alkaloid thioureas efficiently catalyze asymmetric nucleophilic addition of nitromethane to ketimines derived from α-aminophosphonic acids to afford tetrasubstituted α-amino-β-nitro-phosphonates. Catalytic hydrogenation of (S)-α-amino-β-nitro-phosphonate 2d gives enantiopure (S)-α,β-diaminophosphonate 3.