Aromatization-Based Methodology in the Synthesis of Designed and Naturally Occurring Pi Systems with Unusual Structures and Useful Properties

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The overarching objective of the proposed research is to exploit methodology in the field of organic synthesis that has been developed in my group to design and synthesize polycyclic aromatic and heteroaromatic compounds with unusual structures and/or potentially useful properties. The synthesis of molecules with unusual structures is challenging because such systems are necessarily high in energy. The methodology used by my group to generate energetically unfavourable (and therefore very interesting and potentially useful) molecules owes its success to reactions that result in the formation of one or more "aromatic" rings. These energetically advantageous processes offset the disadvantages of forming distorted structures. Bending and battering molecules into shapes that deviate from ideal parameters in a systematic fashion provides an opportunity to learn about the relationships between changes in structure and changes in properties. This knowledge may then be used to design molecules with tailored properties, which may prove to be useful for a variety of applications, include sensors and optoelectronic devices. The research described in this proposal hinges upon a "valence isomerization / dehydrogenation" reaction, which affords severely bent polycyclic aromatic systems, and a multicomponent reaction based on the "inverse electron demand Diels-Alder" reaction, which affords complex heteroaromatic compounds in one fell swoop from three separate starting materials. Prominent polycyclic aromatic targets are molecular helixes, half-belts, belts and Möbius strips. Not only are these systems of considerable fundamental interest, but (in the case of the belts) may also serve as seeds for the controlled growth of "single chirality" single-walled carbon nanotubes. This would provide a solution to an unsolved problem in the field of materials science. The multicomponent reaction will be used to gain rapid access to a variety of polycyclic aromatic and heteroaromatic systems, including biologically active natural products and their analogues, helical molecules and inherently chiral fluorescent compounds.