ChemInform Abstract: Catalytic Asymmetric Protonation of Achiral Lithium Enolates Mediated by a Chiral Tetraamine Ligand with Water as a Proton Source.

Abstract

Abstract Catalytic protonation of achiral lithium enolates (derived from 2-substituted-1-tetralones), mediated by a chiral tetraamine ligand [( R , R )- N , N ′-bis[1-phenyl-2-(1-piperidinyl)ethyl]-1,3-propanediamine (0.10 equiv.)], was achieved with high enantioselectivity (up to 93% ee) by using water (10% aqueous citric acid) as a proton source. A possible mechanism of highly efficient catalytic turnover of the chiral tetraamine ligand is discussed.