Iridium-Catalyzed Enantioselective Hydrogenation of α,β-Unsaturated Carboxylic Acids with Tetrasubstituted Olefins.

A highly efficient asymmetric hydrogenation of α,β-unsaturated carboxylic acids with tetrasubstituted olefin catalyzed by chiral spiro iridium complexes has been developed for the preparation of chiral α-substituted carboxylic acids in excellent enantioselectivities (up to 99% ee). [ABSTRACT FROM AUTHOR]