Supramolecular Catalysis with Self‐Assembled Capsules and Cages: What Happens in Confined Spaces

다국어 초록 (Multilingual Abstract)

The confined space inside self‐assembled capsules or cages provides a unique environment in which organic reactions can be efficiently catalyzed, thanks to the confinement effect of the substrates. In confined spaces the chemical reactions can show unusual mechanisms due to the conformational control of the substrates, steric constrictions, stabilization of species by secondary interactions, and solvent exclusion. Consequently, the classical rules of the organic reactivity are often broken. Thus, many examples reported to data in the literature confirm the paradigm stated by D. J. Cram in 1989: “These carceplexes represent a new state of matter whose interiors are new phase…”. The confined space inside the self‐assembled capsules or cages represents a new phase for the chemical reactivity where there is still so much to explore. In this review we highlight the best‐known cases of reactivity in confined spaces, focusing our attention on the driving forces that drive the encapsulated reactions toward uncommon outcomes. Literature examples that constitute the landmarks in the topic of supramolecular catalysis in confined spaces are also reviewed.
A “new phase of matter”: Supramolecular catalysis in confined space represents a new frontier for the chemical reactivity. In accord with the paradigm of D. J. Cram, the space inside capsules and cages represents a “new phase of matter” where chemical reactions can proceed with uncommon stereo‐ and regiochemical outcomes with respect to the bulk medium. In this review we highlight the best‐known cases of reactivity in confined spaces, and we will discuss the driving forces that drive the encapsulated reactions toward uncommon outcomes.