Phenol-derived chiral phosphine–phosphite ligands in the rhodium-catalyzed enantioselective hydrogenation of functionalized olefins

Abstract

A set of 15 chiral Taddol- and Binol-based phosphine–phosphite ligands were tested in the Rh-catalyzed asymmetric hydrogenation of three olefins, methyl 2-hydroxymethyl-acrylate, 1-phenylvinyl acetate, and α-methyl cinnamic acid. The best enantioselectivities (up to 92% ee) were observed in the hydrogenation of methyl 2-hydroxymethyl-acrylate using Binol-based ligands. As previously observed in other applications of this class of modular chiral ligand in enantioselective catalysis, the stereochemical outcome of the reactions greatly depended on the substituents at the ligand aryl backbone in the ortho-position to the chiral phosphite unit.