The Use of Resorcinarene Cavitands in Metal-Based Catalysis

Catalytic chemistry involving coordination complexes based on resorcinarene cavitands has been little explored in comparison to the many studies concerning the use of such ligands in classical coordination chemistry or host-guest chemistry. The potential utility of resorcinarene cavitands in catalysis arises essentially from two features: (1) their ability to function as ligands suitable for metal confinement and thus to make reactions either shape selective or to enhance their rates through supramolecular assistance by the receptor subunit; (2) their ability to enforce steric interactions with a coordinated metal center and thereby favor carbon-carbon bond forming reactions. To date, limited use has been made of cavitands as platforms for the attachment of different ligating sites, in particular for the generation of multifunctional ligands giving rise to anchimeric assistance in catalytic reactions. This review is intended to show the promise that exists in this area. As generic cavitands can be easily expanded to result in large bowl-shaped structures as well as capsular containers, it may be anticipated that future work in this field will focus on the synthesis of sophisticated, metallated microreactors (possibly made water-soluble) for highly selective transformations, including polymerizations.