Ruthenium(II)-Catalyzed Asymmetric Transfer Hydrogenation of Carbonyl Compounds with 2-Propanol and Ephedrine-Type Ligands

摘要

This account describes the development and application of Noyori's type catalysts based on ruthenium-arene complexes and simple chiral beta-amino alcohols derived from ephedrine, for the asymmetric transfer hydrogenation of 2-propanol to carbonyl substrates. The influenceof key parameters of the catalyst system has been studied systematically, resulting in particular in the design of teh novel ligand (4-biphenylmethyl)norephedrine. Thanks to the latter, the catalytic precursors and true active species could be isolated for the first time, enabling a complete structural description of the catalytic cycle and of probable deactivation pathways. Highly effective applications of those catalysts systems, i.e., the asymmetric reductions of simple aryl ketones and aryl alpha-keto esters, the synthesis of chiral phthalides and syn-beta, delta-dihydroxy esters, are described.