Asymmetric Hydrogenation of Heteroaromatic Ketones and Cyclic and Acyclic Enones Mediated by Cu(I)-Chiral Diphosphine Catalysts

Abstract

Copper(I)-catalyzed asymmetric hydrogenation of heteroaromatic ketones, cyclic and acyclic enones is reported. The choice of the chiral diphosphine ligand highly influenced enantioselectivity as well as chemoselectivity. Highly enantioselective hydrogenation of ortho-substituted heteroaromatic ketones was achieved using BDPP as the ligand. In the 1,2-selective hydrogenation of acylic enone, SEGPHOS gave higher enantioselectivity than BDPP. On the other hand, the bulky ligand DTBM-SEGPHOS had a 1,4-selective nature, leading to the first highly 1,4-selective and enantioselective hydrogenation of cyclic enones.