Preparation of Tröger base derivatives by cross-coupling methodologies

Derivatives of the Tröger base are finding increasing application in supramolecular chemistry: they are introduced as rigid scaffolds into synthetic receptors and 'molecular torsional balances' to quantify weak intermolecular interactions, and serve as efficient 'covalent templates' in the tether-directed remote functionalization of fullerenes. This paper describes the facile synthesis of symmetrically (Schemes 1 and 2) and unsymmetrically (Schemes 4 and 5) substituted Tröger base derivatives starting from the corresponding, readily available dihalo compounds. A variety of metal-catalyzed cross-coupling reactions, including Suzuki couplings, palladium-catalyzed cyanation and boronation, and copper-catalyzed amidations are used to achieve these transformations.