摘要:
Pyrazine-based hydrophilic phosphanes are useful ligands for the ruthenium- and rhodium-catalyzed hydrogenations of acetophenone under hydride transfer and dihydrogen conditions. The effect of alcohol additives on the catalytic, enantioselective aqueous hydrogenation of acetophenone is examined with the newly developed (R,R)-DAMPYPHOS as the ligand and Rh-2(norbornadiene)(2)Cl-2 as the catalyst precursor, giving rise to higher conversions (up to quantitative) and improved enantiomeric excesses (up to 95%) of the formed 1-phenylethanol. (C) 2013 Elsevier Ltd. All rights reserved.