Axially Dissymmetric Bis(aminophosphine)s Derived from 2,2′-Diamino-1,1′-binaphthyl. Synthesis and Application to Rhodium(I)-Catalyzed Asymmetric Hydrogenations

Axially dissymmetric bisphosphine ligands, (R)- and (S)-2,2′-bis(diphenylphosphinoamino)-1,1′-binaphthyl (BDPAB) and (R)-2,2′-bis[N-(diphenylphosphino)methylamino]-1,1′-binaphthyl (Me-BDPAB) were conveniently prepared from 2,2′-diamino-1,1′-binaphthyl. The rhodium(I)-catalyzed asymmetric hydrogenation of α-acylamidoacrylic acids and esters gave the corresponding amino acids of up to 95% optical purity. The sign of the centro-chirality of the product amino acids was always the same to that of the axial chirality of the ligand in both cases of BDPAB and Me-BDPAB.