ABSTRACT
Pt/Al2O3-cinchona alkaloid catalyst system is widely used for enantioselective hydrogenation of different prochiral substrates, such as α-ketoesters [1-2], α,βdiketones, etc. [3-5]. It has been shown that in the enantioselective hydrogenation of ethyl pyruvate (Etpy) under certain reaction conditions (low cinchonidine concentration, using toluene as a solvent) achiral tertiary amines (ATAs: triethylamine, quinuclidine (Q) and DABCO) as additives increase not only the reaction rate, but the enantioselectivity [6]. This observation has been explained by a virtual increase of chiral modifier concentration as a result of the shift in cinchonidine monomer - dimer equilibrium by ATAs [7].
