title: Readily available chiral phosphine-aminophosphine ligands for highly efficient Rh-catalyzed asymmetric hydrogenation of alpha-enol ester phosphonates and alpha-enamido phosphonates.
abstract: A new class of unsymmetrical hybrid phosphine--aminophosphine ligands has been prepared from commercially available, inexpensive (S)-1-phenylethylamine through a concise synthetic procedure. These ligands are not very sensitive to air and moisture, and displayed good enantioselectivities in the Rh-catalyzed asymmetric hydrogenation of various dimethyl alpha-benzoyloxyethenephosphonates bearing beta-aryl, beta-alkyl, and beta-alkoxy substituents and N-benzyloxycarbonyl alpha-enamido phosphonates, in which up to 97% ee was obtained. A side-by-side comparison study disclosed that these new phosphine--aminophosphine ligands showed better enantioselectivity than BoPhoz ligands.
authors.affiliation: Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
authors.forename: Dao-Yong
authors.initials: DY
authors.lastname: Wang
authors.forename: Jia-Di
authors.initials: JD
authors.lastname: Huang
authors.forename: Xiang-Ping
authors.initials: XP
authors.lastname: Hu
authors.forename: Jun
authors.initials: J
authors.lastname: Deng
authors.forename: Sai-Bo
authors.initials: SB
authors.lastname: Yu
authors.forename: Zheng-Chao
authors.initials: ZC
authors.lastname: Duan
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Zheng