Enhancing Hydride Transfer in Catalytic Hydrogenation via σ-Electron-Induced Polarization of Imines.
J Am Chem Soc
; 2024 May 08.
Article
em En
| MEDLINE
| ID: mdl-38717282
ABSTRACT
In this study, we investigated the role of aluminum cations in facilitating hydride transfer during the hydrogenation of imines within the context of Noyori-type metal-ligand cooperative catalysis. We propose a novel model involving aluminum cations directly coordinated with imines to induce activation from the lone pair electron site, a phenomenon termed σ-induced activation. The aluminum metal-hydride amidate complex ("HMn-NAl") exhibits a higher ability of hydride transfer in the hydrogenation of imines compared to its lithium counterpart ("HMn-NLi"). Density functional theory (DFT) calculations uncover that the aluminum cation efficiently polarizes unsaturated bonds through σ-electron-induced activation in the transition state of hydride transfer, thereby enhancing substrate electrophilicity more efficiently. Additionally, upon substrate coordination, aluminum's coordination saturation improves the hydride nucleophilicity of the HMn-NAl complex via the breakage of the Al-H coordination bond.
Texto completo:
1
Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2024
Tipo de documento:
Article