Novel chiral tetraaza ligands(R)-N,N′-bis[2-(piperidin-1-yl)benzylidene]propane-l,2-diamine 6 and(S)-N-[2-(piperidin-l- yl)benzylidene]-3-{[2-(piperidin-1-yl)benzylidene]amino}-alanine sodium salt 7 have been synthesized and fully characterized by NMR,IR,MS and CD spectra.The catalytic property of the ligands was investigated in Ir-catalyzed enantioselective transfer hydrogenation of ketones.The corresponding optical active alcohols were obtained with high yields and moderate ees under mild reaction conditions.
Novel chiral PN_4-type multidentate aminophosphine ligands have been successfully synthesized by Schiff-base condensation of bis(o-formylphenyl)phenylphosphane and various chiral amino-sulfonamides.Their structures were fully characterized by IR,EI-MS and NMR.The catalytic systems,prepared in situ from the multidentate ligands and iridium(I) complexes,showed high activity in asymmetric transfer hydrogenation of propiophenone in 2-propanol solution,leading to corresponding optical alcohol with up to 75%ee.
Shen Luan Yu Yan Yun Li Zhen Rong Dong Juan Ni Zhang Qi Li Jing Xing Gao
