Browsing by Subject "Halogen"

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    Approaches to valuable halogenated products using radical-polar crossover catalysis or halogen transfer to arynes
    (2024-09) Gavin, Joshua
    Molecules with halogen atoms have many applications. In direct applications, halogenated molecules are seen in many marketed pharmaceuticals and continue to represent a growing proportion year-to-year. They also find applications in agrochemicals, polymers, and materials, and the unique properties halogenation imparts to products has been difficult to replicate by other means. Additionally, halogen-containing molecules have indirect applications for many more products because a halogen-free chemical may succeed from a synthetic intermediate containing a halogen atom. Through reactions such as Pd-catalyzed couplings, halogenated materials have become a regular feature in molecular syntheses. Thus, the synthesis of halogen-containing molecules is a vital part toward supporting the growth of the pharmaceuticals, agrochemicals, and materials industries. New methods to access these products in a more efficient manner benefits many industries. This dissertation discusses two distinct strategies to synthesize valuable halogenated products. First, the application of redox-active ligands with transition-metal catalysis is considered especially with early transition metals. The combination of redox-active ligands with relatively redox-innocent early transition metals enabled a method for synthesis of gem-difluorostyrenes. This process occurs via radical-polar crossover, a mechanism new to early-transition metals. Second, synthesis of halogen-containing products was shown by exploiting known reactivity of arynes. This method involves functionalization with amine nucleophiles followed by a rapid halogen-transfer that competes with other undesirable pathways.