A Scaffold Directed Approach to an Aromatic Belt
Connors, David Michael
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An aromatic belt, a molecule that has two continuous edges that do not intersect and is fully conjugated, is a synthetic target that has yet to be isolated. Aromatic belts are an attractive target for synthetic chemists, due to their curved pi system. Molecules with curved pi systems, such as fullerenes and carbon nanotubes, have unique physical and chemical properties. Synthesis of an aromatic belt is challenging, as bending a pi system leads to an increase in strain energy. Our work uses a scaffold to direct the reactions in a controlled manner. The scaffold will allow smaller planer pieces, the "subunits", to be joined together to create a curved precursor. This precursor can then be oxidized to form an aromatic belt. Removal of the scaffold will give the target belt. The scaffold we have chosen is a substituted benzene with three-fold symmetry. This work discusses the synthetic efforts toward cyclophenacene, an aromatic belt with 12 benzene rings arranged in a zig-zag orientation. The synthesis of the sub-units required the development of a novel synthetic route towards tetrasubstituted phenanthrenes. In addition, some previously unreported difficulties with the Mallory photooxidation were encountered and overcome.