Supramolecular catalysis by the resorcin[4]arene hexameric capsule: intra- and intermolecular aromatic allylations and a new aldehyde-isocyanide condensation reaction

Abstract

The levels of specificity and of chemo-, regio-, and enantioselectivity shown by enzymes are unrivalled by artificial catalysts to this day. Non-covalent interactions are at the root of many of the enviable catalytic properties of enzymes. Therefore, chemists have been putting ever greater efforts into designing supramolecular compounds capable of acting as enzyme mimics through tailored non-covalent interactions. One such tool is the hexameric capsule formed by spontaneous assembly of six molecules of resorcin[4]arene in combination with eight water molecules via formation of 60 O–H····O hydrogen bonds. This capsule can include cationic and electron-poor chemical species in its inner cavity, and its catalytic behaviour has long been a subject of research in the laboratory where this thesis work was carried out. Two reactions catalysed by the inner cavity of the resorcin[4]arene capsule are the subject of this work: an unprecedented condensation reaction between an isocyanide and an electron-poor aromatic aldehyde and an aromatic allylation reaction between a substituted allyl cation and an electron-rich aromatic compound. The scope of the reactions was examined, unknown compounds were purified and characterised by NMR spectroscopy and GC-MS and the capsule was shown to impart unique chemo- and regioselectivity.