Boosting the activity of Mizoroki-Heck cross-coupling reactions with a supramolecular palladium catalyst favoring remote Zn…pyridine interactions
Résumé
Transition metal catalysis benefitting from supramolecular interactions in the secondary coordination sphere in order to pre-organize substrates around the active site and reach a specific selectivity typically occur under long reaction times and mild reaction temperatures with the aim to maximize such subtle effects. Herein, we demonstrate that the kinetically labile Zn···N interaction between a pyridine substrate and a zinc-porphyrin site serving for substrate binding is a unique type of non-covalent interaction that enables to identify supramolecular effects in transition metal catalysis after one hour at a high reaction temperature of 130 oC. Under carefully selected reaction conditions, supramolecularly-regulated palladium-catalyzed Mizoroki-Heck reactions between 3-bromopyridine and terminal olefins (acrylates or styrenes) proceeded in a more efficient manner compared to the non-supramolecular version. The supramolecular catalysis developed here displayed also interesting substrate-selectivity patterns.
Domaines
ChimieOrigine | Fichiers produits par l'(les) auteur(s) |
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