title: Synthesis of novel diastereomeric diphosphine ligands and their applications in asymmetric hydrogenation reactions.
abstract: [structure: see text] Diastereomeric biaryl diphosphine ligands 10 and 11 with added chiral centers on the backbone were synthesized. Substrate-directed asymmetric synthesis occurred in the coupling step of the preparation of the diastereomeric diphosphine oxides. The diastereomeric diphosphine oxides were easily separated by column chromatography with silica gel. Ruthenium catalysts containing these ligands were highly effective in the hydrogenation of 2-(6'-methoxy-2'-naphthyl)propenoic acid and beta-ketoesters. The additional chiral centers had a significant influence on the enantioselectivity and activity of the catalysts.
authors.affiliation: Open Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis and Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.
authors.forename: Liqin
authors.initials: L
authors.lastname: Qiu
authors.forename: Jianying
authors.initials: J
authors.lastname: Qi
authors.forename: Cheng-Chao
authors.initials: CC
authors.lastname: Pai
authors.forename: Shusun
authors.initials: S
authors.lastname: Chan
authors.forename: Zhongyuan
authors.initials: Z
authors.lastname: Zhou
authors.forename: Michael C K
authors.initials: MC
authors.lastname: Choi
authors.forename: Albert S C
authors.initials: AS
authors.lastname: Chan