Design of [Mn(i)-Cinchona] catalyst for Asymmetric Hydrogenation of Ketones and β-Keto carbonyl Derivatives.

Herein, we report an efficient [Mncinchona] chiral catalytic system for the asymmetric hydrogenation of ketones, demonstrating a broad substrate scope and high chemoselectivity. The catalyst selectively reduces ketones, while leaving other reducible functional groups, such as olefins, alkynes, nitriles, nitro groups, and esters, unaffected. The solid-state structure of [Mncinchona] complex revealed that the cinchona ligand acts as bi-dentate ligand, providing valuable insights into its coordination environment and reaction mechanism. DFT calculations suggest that hydrogen molecule activation assisted by water molecules occurs a six-membered transition state, with enantioselectivity driven by preferential hydride transfer to the face of the prochiral substrate, resulting in the configuration. This robust catalytic system shows potential for expansion to the reduction of β-ketoesters and γ-ketoamines and is expected to contribute to further advancements in asymmetric hydrogenation.