Organocatalysis in a synthetic receptor with an inwardly directed carboxylic acid.

A cavitand functionalized with a Kemp's triacid derivative was used to catalyze the epoxide ring-opening cyclizations of 1,5-epoxyalcohols. A deep, cylindrical cavity containing electron-rich aromatic walls and an inwardly directed carboxylic acid displayed the necessary characteristics to bind different 1,5-epoxyalcohols and initiate their cyclization reactions. The reactions inside this synthetic receptor occurred in a catalytic and regioselective manner. These results highlight that the arrangement of functionality and unique solvation provided by the structured interiors of natural enzymes can be incorporated into synthetic systems having useful physical and chemical properties.