title: Supramolecular assistance for the selective demethylation of calixarene-based receptors.
abstract: The selective demethylation of methoxy groups of several multifunctionalized 1,3,5-trimethoxycalix[6]arene-based receptors has been achieved. It is shown in this study that the best reagent is trimethylsilyl iodide (TMSI) and that the conformation adopted by the calixarene core is crucial for both the selectivity and the efficiency of the process. A key feature appears to be the "in" or "out" orientation of the methoxy substituents relative to the macrocyclic cavity. If projected inward, the reaction is slow and not selective. If projected outward, the reaction is fast and selective. A strategy that consists of exploiting the host-guest properties of the receptors to change their conformation and to permit their selective demethylation has been developed. Four cases of such a supramolecular assistance are reported, demonstrating the efficiency of the strategy. Such an allosteric control is highly reminiscent of biological processes allowing selective transformation of multifunctional molecules.
authors: †Laboratoire de Chimie Organique, Université Libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium.|‡Unité de Chimie Environnementale et Interactions sur le Vivant, EA 4492, Université du Littoral Côte d'Opale, 145 Avenue Maurice Schumann, MREI 1, 59140 Dunkerque, France.
authors: Pierre-Edouard
authors: PE
authors: Danjou
authors: †Laboratoire de Chimie Organique, Université Libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium.|§Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, Université Paris Descartes, Sorbonne Paris Cité, CNRS UMR 8601, 45 rue des Saints Pères, 75006 Paris, France.
authors: Gaël
authors: G
authors: De Leener
authors: †Laboratoire de Chimie Organique, Université Libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium.
authors: Damien
authors: D
authors: Cornut
authors: †Laboratoire de Chimie Organique, Université Libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium.
authors: Steven
authors: S
authors: Moerkerke
authors: †Laboratoire de Chimie Organique, Université Libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium.
authors: Samir
authors: S
authors: Mameri
authors: †Laboratoire de Chimie Organique, Université Libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium.
authors: Angélique
authors: A
authors: Lascaux
authors: ∥Département de Chimie, Université de Namur (UNamur), Rue de Bruxelles 61, B-5000 Namur, Belgium.
authors: Johan
authors: J
authors: Wouters
authors: §Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, Université Paris Descartes, Sorbonne Paris Cité, CNRS UMR 8601, 45 rue des Saints Pères, 75006 Paris, France.
authors: Andrea
authors: A
authors: Brugnara
authors: §Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, Université Paris Descartes, Sorbonne Paris Cité, CNRS UMR 8601, 45 rue des Saints Pères, 75006 Paris, France.
authors: Benoit
authors: B
authors: Colasson
authors: §Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, Université Paris Descartes, Sorbonne Paris Cité, CNRS UMR 8601, 45 rue des Saints Pères, 75006 Paris, France.
authors: Olivia
authors: O
authors: Reinaud
authors: †Laboratoire de Chimie Organique, Université Libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium.
authors: Ivan
authors: I
authors: Jabin