The use of DPPM and DNPM as chiral modifiers in asymmetric heterogeneous catalytic hydrogenation of isophorone is reported. The effect of solvents and the concentration of reactant, modifiers and catalysts on the enantioselectivity are described. Circular dichroism spectroscopy was used to detect the interaction between the chiral modifier and the substrate. (C) 2002 Elsevier Science B.V. All rights reserved.