Unsymmetrical hybrid ferrocene-based phosphine-phosphoramidites: A new class of practical Ligands for Rh-catalyzed asymmetric hydrogenation

The synthesis and application of a new family of air-stable, highly unsymmetrical ferrocene-based phosphine-phosphoramidites is described. The new ligands exhibit excellent enantioselectivities (over 99% ee) in the Rh-catalyzed asymmetric hydrogenation of enamides, dimethyl itaconate, and methyl (Z)-acetamidocinnamate even with high catalyst turnovers (S/C = 10 000). The binaphthyl moiety is crucial for reactivity and enantioselectivity, and its absolute configuration plays a dominant role in determining the chirality of the hydrogenation products.