Metal–support interaction in Pt/alumina: Inversion of diastereoselectivity by tuning the acid–base properties of the support

The role of metal–support interaction in the hydrogenation of cinchonidine (CD) was studied on acid- and base-doped flame-made Pt/alumina. Analysis of the product distribution revealed that on Pt/alumina and Pt/alumina–silica CD adsorbs on Pt in pro(S) geometry, but doping the support with only 0.25 wt.% Cs2O is sufficient to invert the major adsorption mode to pro(R). The origin of differences between the effect of an acidic additive and support acidity is discussed.