Asymmetric hydrogenation of enamides in aqueous media with a new water-soluble chiral rhodium-α,α-trehalose-derived phosphine–phosphinite catalyst

Abstract

A new chiral rhodium catalyst with α,α-trehalose-derived phosphine–phosphinite (α,α-TREHAPPN) ligand, [(TREHAPPN)Rh(cod)]BF 4 8 has been prepared. This catalyst is soluble in water and is an effective chiral catalyst for asymmetric hydrogenation of N-acyldehydroamino acids in aqueous media to give enantiomerically enriched α-amino acid derivatives with R configuration. The simple decantation allows retrieval of the catalyst from the reaction mixture, the recovered catalyst being re-used without marked loss of enantioselectivity.