C1-Symmetric PNP Ligands for Manganese-Catalyzed Enantioselective Hydrogenation of Ketones: Reaction Scope and Enantioinduction Model

• DOI: 10.1021/acscatal.0c04206
• Publication Date: 2020-11-12T14:30:15Z
• Authors: Liyao Zeng; Huaxin Yang; Menglong Zhao; Jialin Wen; James H. R. Tucker; Xumu Zhang
• Keywords: Moiety; Asymmetric induction; Asymmetric hydrogenation; Catalytic cycle

A family of ferrocene-based chiral PNP ligands is reported. These tridentate were successfully applied in Mn-catalyzed asymmetric hydrogenation ketones, giving high enantioselectivities (92%∼99% ee for aryl alkyl ketones) as well efficiencies (TON up to 2000). In addition, dialkyl ketones could also be hydrogenated smoothly. Manganese intermediates that might involved the catalytic cycle analyzed. DFT calculation was carried out help understand induction model. The Mn/PNP catalyst discriminate two groups with different steric properties by deformation phosphine moiety flexible 5-membered ring.