Asymmetric hydrogenation of ethyl pyruvate over aqueous dispersed Pt nanoparticles stabilized by a cinchonidine-functionalized beta-cyclodextrin

Cinchonidine-functionalized beta-cyclodextrin was used as stabilizing agent for platinum nanoparticles dispersed in water, but also as chiral modifier for the asymmetric hydrogenation of ethyl pyruvate at 30 degrees C under 40 bar of hydrogen. This functionalized cyclodextrin allowed getting more stable, more catalytically active and also more enantioselective Pt nanoparticles compared to control catalytic systems. NMR and MALDI-MS analyses clearly showed the reduction of the vinyl group of the cinchonidine graft during the nanoparticles preparation. Under hydrogen pressure, the hydrogenation of the quinolinic moiety was also proven and can be responsible for the difficulties encountered during the recycling study.