Oxidation reactions are among the most powerful transformations in synthetic organic chemistry because of their ability to increase the functionality of organic substrates. However, the high costs and toxicity of many useful stoichiometric oxidants have prompted substantial effort to develop catalytic transformations that employ readily available and environmentally benign oxidants. A novel pathway for aerobic substrate oxidation is ligand-facilitated palladium oxidation catalysis. These reactions require no redox mediators such as copper(ll) chloride or benzoquinone for dioxygen-coupled oxidation of palladium(0) during catalytic turnover. The proposed research will examine the scope and utility of ligand-facilitated palladium oxidation catalysis for the oxidative hetero- and carbocyclization of olefinic substrates. This work will be facilitated by new parallel screening tools developed in the lab and simultaneous detailed mechanistic characterization of the catalytic reactions. Among the reactions to be developed are new palladium-catalyzed intermolecular oxidative nitrogen-transfer reactions that employ dioxygen as the stoichiometric oxidant. New catalytic oxidations that employ dioxygen as the stoichiometric oxidant have almost unlimited potential in organic chemistry, particularly for the synthesis of natural products and biologically active molecules. Future expansions into asymmetric catalysis would have a significant impact on drug discovery efforts. These reactions are environmentally friendly as well due to their benign by-products (water). These assets, along with the low cost and toxicity of dioxygen, will make ligand-facilitated palladium oxidation catalysis quite attractive to synthetic organic chemists in industry as well as those in academia.
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