Abstract: The efficient chiral Ru₃(CO)₁₂ systems were prepared in situ from Ru₃(CO)₁₂ and various chiral diiminoor diamino-diphosphine tetradentate ligands. The systems have been used for the asymmetric transfer hydrogenation of propiophenone in 2-propanol, leading to 1-phenyl-1-propanol in a 98% yield and 96% e.e. The IR study suggests that the carbonyl hydride anion [HRu₃(CO)₁₁]^- most probably exists as a principal species under the reaction conditions. The high chiral efficiency may be due to the synergetic effect produced by the neighboring ruthenium atoms and a special chiral micro-environment involving the polydentate ligand and the Ru₃ framework.

Key words: Chiral cluster systems, Asymmetric transfer hydrogenation, Aromatic ketones