A Plausible Mechanism for the Iridium-Catalyzed Hydrogenation of a Bulky N-Aryl Imine in the (S)-Metolachlor Process.

ABSTRACT: The hydrogenation of N-(2-ethyl-6-methylphenyl)-1-methoxypropan-2-imine is the largest-scale asymmetric catalytic process for the industrial production of agrochemical (S)-metolachlor. The challenging hydrogenation across the sterically crowded carbon-nitrogen double bond was achieved using a mixture of [IrCl(COD)]₂, (R,S_Fc)-Xyliphos, NBu₄I and acetic acid. Acetic acid was critical in achieving excellent productivity and activity. Despite its industrial significance, a mechanism that explains how the sterically hindered bond in the imine is reduced has yet to be proposed. We propose a plausible proton-first, outer-sphere mechanism based on density functional theory calculations that is consistent with the experimentally observed

SUBMITTER: Kwan AL 

PROVIDER: S-EPMC9414898 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature