Enantioselective hydrogenation of ketopantolactone using Pt–β-ICN chiral catalyst: Correlation between the solution-state concentration of a nucleophilic β-isocinchonine–ketopantolactone complex and enantioselectivity

Experimental evidence (measured by NMR) is given for the correlation between the solution-state concentration of the nucleophilic 1:1 modifier–substrate complex and the ee on enantioselective hydrogenation of ketopantolactone using Pt–β-isocinchonine chiral catalyst. The relationship displays a saturation-type curve, which may indicate an underlying adsorption process involving the catalytically relevant nucleophilic complex.