Switching the selectivity of a polyglycerol dendrimer monomolecularly imprinted with D-(−)-fructose

A polyglycerol dendrimer unimolecularly imprinted with D-(−)-fructose (Fru) was synthesized. The dendrimer formed adducts with several monosaccharides, Fru, D-(+)-galactose, D-(+)-glucose, D-(+)-mannose, and methyl-α-D-mannopyranoside (MMan), by removal of four water molecules. The dendrimer preferred Fru in the absence of N,N,N′,N′-tetramethylmethylenediamine (TMDAM), whereas it preferred MMan in the presence of TMDAM. Developing synthetic receptors for carbohydrates is an important challenge with potential applications in sensing, catalysis, and targeting.1 Altering the selectivity of a carbohydrate receptor in a controllable way would further expand the types of applications available. We recently reported that monomolecularly imprinted dendrimers (MIDs) can act as selective receptors for porphyrins and amines.2 With partial success, these previous studies sought dendrimers with a high cross-linking density to fix recognition sites rigidly for high selectivity. This article reports the synthesis of MIDs with lower cross-link densities whose recognition sites can be repositioned, thus switching the carbohydrate selectivity. The aryl boronic acid group was chosen as the recognition unit because of its well documented ability to for