Nickel-Catalyzed Asymmetric Hydrogenation of Aryl-Substituted Maleic Acid Diesters.

Chiral aryl-substituted succinic acid diesters are valuable intermediates for the synthesis of wide range of chiral bioactive molecules, yet their enantioselective synthesis remains a significant challenge. Herein, we report the first example of a nickel-catalyzed asymmetric hydrogenation of aryl-substituted maleic acid diesters. This catalytic system exhibits a broad substrate scope and good functional-group tolerance, delivering the target products in up to 99% isolated yield and 97% ee (enantiomeric excess). The resulting succinic acid diesters can be readily converted into a variety of structurally diverse chiral derivatives. Mechanistic studies, including deuterium-labeling experiments and kinetic analysis, were conducted to elucidate the catalytic cycle, and a plausible reaction pathway is proposed.