Chiral phosphine-phosphoramidite ligands for highly enantioselective hydrogenation of N-arylimines

The asymmetric hydrogenation of N -arylimines with the chiral phosphine-phosphoramidite ligand, ( S c , S a )-PEAPhos 2b , has been developed. The results revealed that the presence of the substituents on the 3,3′-positions of the binaphthyl backbone significantly improved the enantioselectivity. The utility of this methodology was demonstrated in the synthesis of the chiral fungicide ( R )-metalaxyl.