Binding of ion pairs in a thiourea-functionalized self-folding cavitand

Abstract

We report the synthesis of a new synthetic cavitand receptor with an embedded thiourea moiety directed at effective molecular recognition of ion pairs. Initial prospects towards the use of cavitands in biomimetic carbocationic cyclizations have been carried out, employing ionic guests as stable surrogates for putative substrates and intermediates. The cavitand displays tight binding with tetramethylammonium salts, with unforeseen slow exchange kinetics of both cation and anion componentsWe thank MINECO – Spanish Government (“Ramón y Cajal” grant to A. L. RYC2012-11112, CTQ2014-54306-P, and CTQ2014-61629-EXP), Generalitat de Catalunya, 2014SGR931, and Universitat de Girona (MPCUdG2016/096) for financial suppor

En route to terpene natural products utilizing supramolecular cyclase mimetics

“…A main difference to enzymes is the general absence of a pyrophosphate-binding motif, which is essential for strong substrate binding in cyclase enzymes. However, the Lledó group reported a supramolecular cavitand equipped with an anion binding motif, 33 but was not able to initiate cyclizations so far. The groups of Toste, Bergman and Raymond reported monoterpenelike Prins-cyclizations inside the anionic metal-ligand cage (AE)-I (Scheme 4b).…”

Calix[5]arene Self‐Folding Cavitands: A New Family of Bio‐Inspired Receptors with Enhanced Induced Fit Behavior

“…The platform devised by Rebek allows functionalization of one of the cavitand's wall, giving rise to the development of interesting applications such as the isolation of reactive intermediates or the development of bioinspired and supramolecular catalysis. [9] Despite all these feats, we identified some downsides of the R4A derived selffolding cavitands that limit the development of new and meaningful applications, specifically in the area of catalysis. First, the binding space of these cavitands is relatively reduced, limiting the choice of guests to small molecules and substrates of limited relevance.…”