| The formation of the aryl-aryl bond is one of the most important and one of the most used carbon-carbon bonds in synthetic organic chemistry. Molecules with such bonds are prevalent in natural products, in synthetic polymers and in materials chemistry. In many cases, this bond formation is catalyzed by a palladium species. Motivated by the potential reduction in cost and the ability to convert phenols to biphenyls through the corresponding aryl sulfonates, we have explored the effects of using nickel as a catalyst in the Suzuki cross-coupling and in the synthesis of oligophenylenes.;Nickel has been previously used as a catalyst for the Suzuki cross-coupling. However, no general method had been brought forward to cross-couple a wide variety of aryl sulfonates. In the first chapter, we present that NiCl2(dppe) is a general catalyst for a variety of electron-rich and electron-poor aryl mesylates. NiCl2(dppe) cross-couples electron-rich aryl sulfonates as long as additional PPh3 is added. For electron-withdrawing complexes, added dppe is sufficient, however, a catalytic system with added PPh 3 was more suitable and more reactive.;In the last four chapters, we show studies in the nickel-catalyzed synthesis of poly(m-phenylenes) from functionalized meta-bismesylates. This was motivated by the ability to synthesize helical structures. We were also motivated by the ability to synthesize model helical and linear structures and test their antimicrobial properties. We show that a significant and well-known side reaction, phenyl transfer from ligand occurs much more readily when an electron-withdrawing group is ortho/para to the growing chain rather than meta. We also attempted to synthesize oligo( m-phenylenes). The attempts to synthesize amine-functionalized oligo( m-phenylenes) were inspired by potential biological or material application that the resultant suprastructures would have. We also show that in order to obtain amine-functionalized oligo(m-phenylenes) in good yield and fair molecular weight that both the basicity of the nitrogen atom and the acidity of the hydrogen atom must be accounted for. It was found that, despite difficulties with solubility and protecting group removal, imides are the best protecting group for the nickel-catalyzed polymerization of amine-functionalized bismesylates to form oligo(phenylenes). |
