Influence of Achiral Tertiary Amines on the Enantioselective Hydrogenation of α,β-diketones Over Cinchonidine-Pt/Al2O3 Catalyst

摘要

Enantioselective hydrogenation of 2,3-butanedione and 3,4-hexanedione has been studied over cinchonidine -Pt/Al2O5 catalyst system in the presence or absence of achiral tertiary amines (quinuclidine, DABCO) using solvents such as toluene and ethanol. Kinetic results confirmed that (i) added achiral tertiary amines increase both the reaction rate and the enantioselectivity, (ii) both substrates have a strong poisoning effect, (iii) an accurate purification of the substrates is needed to get adequate kinetic data. The observed poisoning effect is attributed to the oligomers formed from diketones.