Rapid Synthesis of Chiral 1,2-Bisphosphine Derivatives through Copper(I)-Catalyzed Asymmetric Conjugate Hydrophosphination

1,2-Bisphosphines have been identified as one class of important and powerful chiral ligands in asymmetric catalysis with transition metals. Herein, a copper(I)-catalyzed asymmetric hydrophosphination of alpha,beta-unsaturated phosphine sulfides was developed with the assistance of soft-soft interaction between copper(I)-catalyst and the phosphine sulfide moiety, which afforded 1,2-bisphosphine derivatives with diversified electronic nature and steric hindrance in high to excellent yields with high to excellent enantioselectivity. Moreover, the challenging catalytic asymmetric hydrophosphination/protonation reaction was achieved with excellent enantioselectivity. Strikingly, the dynamic kinetic resolution of racemic diarylphosphines was also successfully carried out with high to excellent diastereo- and enantioselectivities. Interestingly, the nucleophilic copper(I)-diphenylphosphide species was characterized by P-31 NMR spectrum and mass spectrum. At last, three products were transformed to chiral 1,2-bisphosphines, which were employed as ligands in Rh-catalyzed asymmetric hydrogenation of alpha-amino-alpha,beta-unsaturated ester. The alpha-amino acid derivative was produced in high enantioselectivity, which demonstrated the utility of the present methodology.