New chiral catalysts for reduction of ketones.
The condensation of o-(diphenylphosphino)benzaldehyde and various chiral diamine gives a series of diimino-diphosphine tetradentate ligands, which are reduced with excess NaBH4 in refluxing ethanol to afford the corresponding diaminodiphosphine ligands in good yield. The reactivity of these ligands toward trans-RuCl2(DMSO)4 and [Rh(COD)Cl]2 had been investigated and a number of chiral Ru(II) and Rh(I) complexes with the PNNP-type ligands were synthesized and characterized by microanalysis and IR, NMR spectroscopic methods. The chiral Ru(II) and Rh(I) complexes have proved to be excellent catalyst precursors for the asymmetric transfer hydrogenation of aromatic ketones, leading to optically active alcohols in up to 97% ee.
Gao
J X
JX
Department of Chemistry, Institute of Physical Chemistry, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian, P.R. China. jxgao@xmu.edu.cn
Zhang
H
H
Yi
X D
XD
Xu
P P
PP
Tang
C L
CL
Wan
H L
HL
Tsai
K R
KR
Ikariya
T
T
D002621:Chemistry / Q000379:methods; D006859:Hydrogen / Q000737:chemistry; D007659:Ketones / Q000378:metabolism*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D012428:Ruthenium / Q000737:chemistry*; D017975:Ruthenium Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D013237:Stereoisomerism
D007659:Ketones; D008024:Ligands; D017975:Ruthenium Compounds; D012428:Ruthenium; D006859:Hydrogen