Manganese‐Catalyzed Chemoselective Direct Hydrogenation of α,β‐Epoxy Ketones and α‐Ketoamides at Room Temperature

Abstract

Chemoselective hydrogenation of α,β‐epoxy ketones and α‐ketoamides is achieved at room temperature (25 °C) using 2.0 bar H<sub>2</sub> and a pincer‐ligated Mn(I) catalyst that provides synthetically valuable α‐hydroxy epoxides and α‐hydroxy amides. This protocol applies to a wide range of alkyl and aryl‐substituted α,β‐epoxy ketones, including terpenes (α‐ionone, nootkatone, and R‐carvone)‐ and steroids (testosterone and progesterone)‐derived epoxy ketones, and tolerates H<sub>2</sub> sensitive functionalities, such as halides, acetyl, nitrile, nitro, epoxide, alkenyl and alkynyl groups. Additionally, the α‐ketoamides bearing reducible functional groups, including acetyl and diazo benzene, were untouched under this protocol and selectively converted to α‐hydroxy amides. A preliminary mechanistic study highlighted the metal‐ligand cooperative H<sub>2</sub> activation process.