Several different mechanisms have been proposed so far, for the enantioselective heterogeneous hydrogenation of pyruvic acid esters. However, even considering the different reactions` media used in these reactions, there are considerable theoretical and experimental evidences supporting that quinoline ring must be adsorved on the catalyst surface. In that way, there is enough energy to allow the selection of a suitable intermediate, resulting from the interaction of dihydrocinchonine (or dihydrocinchonidine) and pyruvic acid esters that ought to result in the observed enantioselectivity.