The Synthesis of Highly Substituted Cyclooctatetraene Scaffolds by Metal-Catalyzed [2+2+2+2] Cycloadditions: Studies on Regioselectivity, Dynamic Properties, and Metal Chelation

摘要

Cyclooctatetraenes (COTs) are a fascinating class of molecules with great potential utility as building blocks for synthesis, scaffolds for drug discovery, designed carbohydrate mimics, ligands for d- and f-block metals including those for asymmetric catalysis, and components for molecular detection devices (e.g. dynamic molecular tweezers) and novel materials. For many applications including the use of COTs in fluxional materials, conducting polymers, and light emitting devices, the type and degree of COT substitution play a critical role in controlling the redox and electronic properties of the system. For other applications, substitution determines COT topological chirality and the rate of COT racemization by tub-to-tub ring inversion. Notwithstanding their considerable potential, highly substituted and functionalized COTs have received limited attention partly due to the relative paucity of methods for their general and efficient synthesis.