The enantioselective hydrogenation of ethyl pyruvate was investigated over a catalytic system consisting of a Pt/Al2O3 catalyst containing silicium organic moieties anchored to the support and cinchonidine, the chiral template molecule. The Si(CH3)(2)R moieties (where R=-CH3 or -C8H17) were anchored to the alumina via surface reaction of silicium organic compounds and the surface OH groups of the support. The introduction of -Si(CH2)(n)R moieties onto the alumina significantly decreased both the rate and the enantioselectivity of the hydrogenation reaction. The decrease of the enantioselectivity indicates that the enantio-differentiation step is more complex than it is predicted by the existing models. The results also show that the enantio-differentiation step cannot be exclusively attributed to the interaction between the half-hydrogenated substrate and cinchonidine taking place at the platinum surface.