Resorcin[4]arene Hexamer: From Nanocontainer to Nanocatalyst

The hydrogen-bonded hexameric capsule formed by the self-assembly of six resorcin[4]arene units with eight water molecules provide a unique pseudo-spherical nano-environment. The cavity of the capsule was exploited as a well-defined nanoreactor to host cationic reagents for stoichiometric reactions or cationic metal catalysts to impart unique substrate and product selectivities. Moreover, the high electron density of the inner surface of the capsule enabled its use as a self-assembled supramolecular organocatalyst for a series of reactions involving cationic intermediates such as alkyne and isonitrile hydrations, epoxide isomerization, synthesis of heterocycles such as tetrazoles and 4,5-dihydro-1 H -pyrazole derivatives, and sulfoxidation reactions through activation of hydrogen peroxide by means of hydrogen-bonding.