Ruthenium(II) and rhodium(III) catalyzed asymmetric transfer hydrogenation (ATH) of acetophenone in isopropanol and in aqueous sodium formate using new chiral substituted aromatic monosulfonamide ligands derived from (1R,2R)-diaminocyclohexane
摘要:
A series of aromatic monosulfonamide ligands derived from (1R,2R)-diaminocyclohexane were synthesized with electron withdrawing and donating groups. These were complexed with Rh(Cp*) or Ru(arene) and their catalytic efficiencies were compared in the ATH of acetophenone using sodium formate/water or isopropanol/KOH as the hydrogen source. Results suggest that substituents on the benzene ring of the sulfonamide have very little electronic impact on the enantioselectivity and mechanism of the reaction. (C) 2008 Elsevier Ltd. All rights reserved.