title: Ru(II)-SDP-complex-catalyzed asymmetric hydrogenation of ketones. Effect of the alkali metal cation in the reaction.
abstract: The Ru(II) complexes of SDP and DPEN combined with t-BuOK in 2-propanol formed a very effective catalyst for the hydrogenation of simple aromatic ketones with high activity and enantioselectivity. The racemic alpha-arylcycloalkanones can also be hydrogenated by this system, providing alpha-arylcycloalkanols in excellent cis/trans stereoselectivity (>99:1) and enantioselectivity (up to 99.9%) for the cis isomer. In the study of the effect of the alkali metal cation in the hydrogenation of acetophenone using RuCl(2)(Tol-SDP)(DPEN) and RuCl(2)(Xyl-SDP)(DPEN) catalysts, we found that t-BuONa provided a faster reaction than t-BuOK, which indicated that the sterically hindered diphosphine ligands preferred the base with the smaller metal cation.
authors.affiliation: State Key Laboratory and Institute of Elemento-organic Chemistry, Nankai University, Tianjin 300071, China.
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Xie
authors.forename: Sheng
authors.initials: S
authors.lastname: Liu
authors.forename: Xiang-Hong
authors.initials: XH
authors.lastname: Huo
authors.forename: Xu
authors.initials: X
authors.lastname: Cheng
authors.forename: Hai-Feng
authors.initials: HF
authors.lastname: Duan
authors.forename: Bao-Ming
authors.initials: BM
authors.lastname: Fan
authors.forename: Li-Xin
authors.initials: LX
authors.lastname: Wang
authors.forename: Qi-Lin
authors.initials: QL
authors.lastname: Zhou