Asymmetric hydrogenation of ketones using Ir(III) complexes of N-alkyl-N′-tosyl-1,2-ethanediamine ligands

The combination of an enantiomerically pure N'-alkylated derivative of N-4-toluenesulfonyl-1,2-diphenylethane-1,2-diamine (TsDPEN) with iridium trichloride results in the formation of a catalyst with high selectivity for ketone hydrogenation. Products with enantiomeric excesses of up to 84% were formed. The best results were obtained using a ligand with an n-alkyl chain and ortho-substituted acetophenone derivatives and other hindered derivatives. (C) 2008 Elsevier Ltd. All rights reserved.