The hydrophobic cavity of macrocyclic host molecules provides unique opportunities to mimic and better understand the binding pockets of enzymes. It is ideally suited to bring two molecules, which are supposed to react, into close spatial proximity, it aligns and confines molecules into its space, and alters their reactivity by providing a microenvironment, which differs from that in solution.

We have used supramolecular cavities for thermally and photochemically activated reactions. For example, we have developed a simple supramolecular approach to metalloenzyme models in aqueous solution, which is based on the dynamic self-assembly of a ternary complex consisting of macrocyclic host, organic guest, and a transition metal cation. This supramolecular ensemble served as a phase-transfer catalyst and gave unprecedented product distributions in photochemically activated deazetation reactions. In another example, we also investigated thermally activated retro-Diels–Alder reactions inside cucurbiturils in the gas phase by using a mass spectrometric study combined with quantum-chemical calculations.

Key references: (a) Chem. Soc. Rev. 2015, 44, 394-418; (b) Nature Chem. 2013, 5, 376-382; (c) Angew. Chem. Int. Ed. 2011, 50, 545-548; (d) Angew. Chem. Int. Ed. 2006, 45, 7400-7404.