Abstract

Due to their unique chemical, physical and photophysical properties, organoboron compounds and in particular triarylboranes play a central role in chemistry and in catalysis. Trivalent neutral boron Lewis acids, which are planar trigonal species, have been shown to exhibit enhanced Lewis acidity and electrophilicities when constrained in a pyramidal trigonal environment. Within the context of the emerging area of geometrically constrained main-group elements, the fundamental experimental and computational investigations of the impact of structural deformation on the physicochemical properties and reactivity of borane derivatives is of interest. This thesis will explore successively the development of geometrically constrained intramolecular FLP and of cationic boron Lewis superacid based on the aza-boratriptycene scaffold, then the synthesis of pyramidalyzed electron-deficient borenium cation with tethered pyridine and NHC ligands embedded in the triptycene scaffold and will finally focus on chiral borenium cations as new Lewis acids. A collaborative work dealing with the combination of the strong 9-sulfonium-10-boratriptycene with hindered Lewis bases is finally performed for developing latent FLP. This work deepens our understanding of the synthesis of constrained boron Lewis acids species, a key step to develop new pyramidal boron Lewis superacids, deblocking new kinds of reactivity in main-group chemistry. For instance, electrophilic Csp2–H borylation reactions of electron-poor aromatics were observed, new unusual binding mode at weakly coordinating anions were discovered and encouraging steps were initiated for reaching new chiral boron-based Lewis acids, opening the path toward new horizons in main-group chemistry.

Jury

  • Prof. Benoît CHAMPAGNE (UNamur), Président
  • Prof. Guillaume BERIONNI (UNamur), Secrétaire
  • Prof. Olivier CHUZEL (Aix-Marseille Université)
  • Prof. Raphaël ROBIETTE (UCLouvain)
  • Prof. Stéphane VINCENT (UNamur)