Cavitand boronic acids mediate highly selective fructose transport.

The synthesis sugar-transport properties of a family of five cavitand rim-appended boronic acids are reported. These conformationally rigid compounds are not observed to leach out of lipophilic membranes, and they exhibit unprecedented fructose to glucose transport selectivities and give higher fluxes than other neutral boronic acids. These properties make the cavitand boronic acids the best artificial fructose transporters described thus far. [structure: see text]