Cucurbiturils in supramolecular catalysis

Nearly 80 years following the initial synthesis of cucurbiturils, its structure was finally revealed in 1981, which discovery opened the field for further investigation. As a result, the scope of available sizes and varieties of cucurbiturils has grown profoundly in the last four decades, leading to a large number of potential applications, including cucurbiturils in catalysis as supramolecular additives due to the capability of supramolecular binding to certain substrates. Owing to their polar portals and non-polar cavity, cucurbiturils can have an eclectic range of binding versatile guests of different shapes and electronic structures, making them especially attractive for supramolecular catalysis with a wide range of possible reaction types. This review concisely discusses the unique structure and properties of cucurbiturils, and highlights their use as molecular containers in terms of supramolecular interactions in catalytic reactions such as photoreaction, solvolysis, oxidation, metal-assisted catalysis, bromination, Diels–Alder, xanthene synthesis, and Schiff base reaction.