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 (1 R,2 R)-diaminocyclohexane

Abstract

A series of aromatic monosulfonamide ligands derived from (1 R,2 R)-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.