Cobalt-Catalyzed Asymmetric Hydrogenation of α-Hydroxy Ketones Enabled by a Carboxylic Acid Additive Promotion Strategy.

Highly enantioselective hydrogenation of α-hydroxy ketones was achieved by applying the catalytic combination of cobalt acetate and chiral Ph-BPE ligand, supplemented by a carboxylic acid additive promotion strategy. The carboxylic acid additive significantly increases both reactivity and enantioselectivity, allowing for the highly efficient generation of chiral 1,2-diols with up to 99% ee. The application utility is proved through derivations and a total synthesis of (R)-(-)-eliprodil. Mechanistic studies, including control experiments and DFT calculations, support the proposed catalytic mechanism and explain the origin of enantioselectivity.