UC Irvine

The utility of transition metals as mediators of chemical transformations cannot beunderstated. Transition metal complexes are capable of catalyzing a vast variety of reactions, from cross-coupling and cross-electrophile coupling reactions that allow for the synthesis of structurally diverse molecules, to CO2 valorization to generate fuel. For catalysis that focuses on the construction of privileged motifs for the production of new drugs or bioactive materials, a major concern is chemoselectivity and variety of reagents available as coupling partners. One method in particular that seeks to address this is cross-electrophile coupling, which typically exploits Ni catalysts to differentiate between electrophilic coupling partners. The coupling partners can also contain non-traditional electrophiles, such as amines or sulfonamides. Research efforts focused on decreasing the impact of CO2 emissions must work to design processes that generate high-value products without requiring a high input of energy. One method that addresses this concern is combined CO2 capture and CO2 conversion, where electrochemistry can be utilized to perform CO2 conversion under mild conditions. Many complexes typically used in harsh hydrogenation reactions may be repurposed as electrocatalysts. Chapter 1 and Chapter 2 describe the design of new Ni-catalyzed cross-coupling and cross-electrophile coupling reactions. These new methods exploit Ni’s capacity to engage sluggish electrophiles and demonstrate the use of sulfonamide C–N bonds as reliable coupling partners. Chapter 1 shows the scope of a new Kumada cross-coupling reaction that avoids β-hydride elimination with β-branching substrates. Chapter 2 details the domino cross-electrophile dicarbofunctionalization of propargyl piperidines to afford highly functionalized vinyl cyclopropanes. Chapter 3 details the exploration of an isolated dihydride, formed by reducing the commercially available hydrogenation catalyst Ru-MACHO®, which demonstrates the ability to convert CO2 and carbamate to formate.