Copper(I)-catalyzed asymmetric hydrophosphination of alkenyl azaarenes

Hydrophosphination of α,β-unsaturated carbonyl compounds is one of the most common methods to prepare chiral phosphines. Herein, a copper(I)-catalyzed asymmetric hydrophosphination of alkenyl azaarenes is developed by virtue of the electron-withdrawing nature of the azaaryls. For one thing, the addition of diarylphosphines to 2-alkenyl 1 H -benzo[ d ]imidazoles, 2-alkenyl benzo[ d ]oxazole, and 2-alkenyl benzo[ d ]thiazole furnishes an array of chiral phosphines bearing a carbon stereogenic center in high yields with high enantioselectivity. For another, the dynamic kinetic addition of unsymmetrical diarylphosphines to a variety of vinyl azaarenes provides P -chiral phosphines in moderate to excellent yields with moderate to high enantioselectivity. Finally, three C -chiral phosphines bearing a benzo[ d ]oxazole ring are isolated from the reaction mixtures and used as chiral ligands in Rh-catalyzed enantioselective hydrogenation of α-amino-α,β-unsaturated esters. Eight chiral α-amino acid derivatives were prepared in high enantioselectivity, demonstrating the synthetic utility of the present methodology in asymmetric catalysis. A copper(I)-catalyzed asymmetric addition of diarylphosphines to alkenyl azaarenes is developed, which constructs either C -chiral or P -chiral tertiary phosphines generally in high yields with high enantioselectivity. ( R , R )-QUINOXP* works as the best ligand in the former event while ( R , R )-Ph-BPE serves as the most efficient ligand in the latter event. Three chiral phosphines generated from 2-alkenyl benzo[ d ]oxazole are isolated without quenching the reaction, which are successfully used as P,N-bidentate ligands in Rh-catalyzed asymmetric hydrogenation of α-amino-α,β-unsaturated esters.