Transimination reactions in [b-3C-im][NTf2] ionic liquid

Abstract

Compared to conventional molecular solvents, the ionic liquid [b-3C-im][NTf₂] was found to promote transimination reactions with up to ∼100-fold rate enhancement. This rate effect observed at ambient temperature might be explained by the fact that the ionic liquid displays weak Lewis acidity with very low, if any, nucleophilicity and its imidazolium cation is expected to interact by associating with, and thus electrophilically activating, the CN bond of the starting imine, leading to increased stabilization of the polar, charged intermediate species and ultimately, rapid product formation. Moreover, the presence of 1 mol% Sc(OTf)₃ in [b-3C-im][NTf₂] further facilitates the transimination reactions studied.