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 multidentate P3N4-type ligand has been synthesized and characterized by NMR and HRMS.Using i-PrOH as solvent and hydrogen source, asymmetric transfer hydrogenation of various ketones was investigated. The catalyst generated in situ from chiral multidentate aminophosphine ligand（R,R,R,R）-3 and IrCl（CO）（PPh3）2exhibited highly catalytic activity and excellent enantioselectivity under mild conditions, achieving the corresponding chiral alcohols with up to 99% yield and 99% ee.
A series of novel chiral C_2-symmetric multidentate aminophosphine ligands have been successfully synthesized by Schiff-base condensation of bis（o-formylphenyl）phenylphosphane and easily available monoprotected（1R,2R）-diaminocyclohexane.The catalytic properties of these ligands were investigated in Ir-catalyzed asymmetric transfer hydrogenation of various aromatic ketones,giving the corresponding optical active alcohols with up to 98%conversion and good ee under mild reaction conditions.
The new polydentate mixed-N,P,O chiral ligands have been synthesized by the condensation of bis（o-formylphenyl）- phenylphosphane and R-phenylglycinol in CHCl_3,and fully characterized by IR,NMR and EIMS spectra.These ligands were employed with a simple Ni complex Ni（PPh_s）_2Cl_2 in situ as catalytic systems for asymmetric transfer hydrogenation of ketones,and the corresponding optical alcohols were obtained with up to 84%ee under mild conditions.
Zhen Rong DongYan Yun LiShen Luan YuGuo Song SunJing Xing Gao
