Synthesis via Decarboxylative Activation

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The Chemical Synthesis Program of the Chemistry Division supports the project by Professor Tunge. Professor Tunge is a faculty member in the Department of Chemistry at The University of Kansas. He is developing new classes of reactions that are less harmful to the environment than current state-of-the-art technologies. To do this, Professor Tunge and his group harness the chemical potential inherent in carboxylic acids. These groups are very common and can be found in a wide variety of readily available, renewable materials. By developing methods that take advantage of carboxylic acids, the Tunge group is able to convert these readily available materials into more valuable chemicals. This is accomplished by the novel combination of two types of chemical reagents that in turn lowers the energy barrier to reactions that were previously unavailable. This leads to new types of chemical reactivity. In the specific project being pursued the carboxylic acid is stripped out of the molecule to form a highly reactive intermediate that can then be used to generate new chemical bonds. In addition to its scientific value, this combination of environmentally friendly reagents to achieve synthetic goals provides an excellent vehicle for training students to make chemicals and materials in a wide variety of industries. Professor Tunge's group is also engaged in scientific outreach in catalysis education and is developing new avenues for recruitment of underrepresented groups into the chemistry profession. Carboxylic acids are a ubiquitous, often renewable source of organic reactants. Past chemistries have allowed the Tunge group to transform carboxylic acids into a variety of chemicals using decarboxylation to form reactive nucleophiles (pKa 10-32). In this project, carboxylic acids are being combined with transition metal catalysts in combination with photoredox catalysts to form reactive nucleophiles of high basicity (pKa 32-48), thus obviating the need for stoichiometric organometallic reagents. In addition to using carboxylic acids as carbanion equivalents, new strategies are being developed that allow decarboxylation to be used to generate radical and carbocation intermediates. Ultimately, these studies are being employed to determine optimal conditions for generating specific reactive intermediates and then exploiting those intermediates through C-C bond forming, elimination, and nucleophilic trapping reactions. This chemistry integrates the themes of catalysis with green chemistry and synthesis. These themes are further emphasized in educational materials related to catalysis that are broadly disseminated online.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.