Selective distal functionalization of resorcinarenes via an ortholithiation approach

[摘要] ENGLISH ABSTRACT: Resorcinarenes are tetramers, belonging to a class of [1]4metacyclophanes, easily formed by the acid- or base-catalysed condensation of resorcinol and aldehydes. Properties include, amongst others; bowl-like shape, adhesion to hydrophilic surfaces and formation of hexameric capsules. Their uses are, to mention some: components in liquid crystals, photoresistors, selective membranes, surface reforming agents, HPLC stationary phases, ion-channel mimics, metal-ion extraction, molecular switches and ligands for metal catalysts. Selective functionalization of resorcinarenes has been explored and achieved via relatively inefficient methodologies which limit studies, structural architecture and new applications. In this work, synthesis of C4v symmetric resorcinarene ethers was performed which were used as templates in undertaking studies towards selective derivatisation of resorcinarenes via an ortholithiation approach.Conditions for the efficient synthesis of distally substituted resorcinarenes using ortholithiation were optimized and tested with a range of electrophiles, lower rim lengths, scale, base equivalents, reaction times and solvent effects. Ortholithiation gave distally substituted resorcinarenes in reasonable yields (>80%).Ortholithiation and its ability to form distal-resorcinarene esters could possibly be used as a way to synthesize distal-chloromethyl resorcinarene precursors whose further functionalization would furnish a range of distal-resorcinarene imidazolium salts, a class of distal bidentate carbene ligand staring materials for transition metal coordination.

[发布机构] Stellenbosch University