The combination of ATR−IR and modulation spectroscopy allowed for the study of the interaction of ketopantolactone with Pt/Al2O3 films chirally modified by cinchonidine under hydrogenation conditions. The spectra reveal a significant influence of ketopantolactone on the adsorption of the modifier and indicate a N−H−O hydrogen bond between modifier and reactant. The latter was corroborated by a comparative study with N-methyl cinchonidine chloride modified Pt/Al2O3.