Catalytic Asymmetric Hydrogenation of [alpha]-CF3- or [beta]-CF3-Substituted Acrylic Acids using Rhodium(I) Complexes with a Combination of Chiral and Achiral Ligands

Only the mixture works! Acrylic acid derivatives with CF3 substituents in α or [beta]position were efficiently hydrogenated in the presence of a Rh(I) complex with a chiral secondary phosphine oxide (SPO; see scheme) and an achiral Ph3 P as ligands. The corresponding propanoic acid derivatives were obtained with generally high conversion (>99%) and high enantioselectivity (92->99%).