With this award, the Chemical Catalysis Program of the Division of Chemistry is funding Professor Ross Widenhoefer in the Department of Chemistry at Duke University for fundamental studies of catalytic reactions based upon the element, gold, that enable the efficient transformation of simple organic molecules into more complex ones. New catalytic methods that efficiently and selectively transform organic compounds into higher value products have the potential to transform various classes of chemical production. Within this project, the mechanisms of specific reaction steps involved in gold-catalyzed reactions are being carefully investigated for their optimal application in chemical transformations. The proposed research activities are being integrated into the scientific education and training of the graduate and undergraduate student researchers, including students from groups traditionally underrepresented in the sciences. Graduate students are participating in educational activities offered through the Duke University Graduate School. Graduate students and undergraduate students are also performing community outreach activities and developing demonstrations related to catalysis and coordination chemistry.
Professor Widenhoefer is investigating the mechanisms of gold(I) pi-activation catalysis, including the hydrofunctionalization of carbon-carbon multiple bonds and the cycloaddition of enynes and related substrates. Despite a growing body of work in this area, limited experimental information is available regarding the mechanisms of the gold(I)-catalyzed hydrofunctionalization of carbon-carbon multiple bonds and, likewise, little direct experimental information is available regarding the structure and reactivity of cationic gold carbene complexes and cationic intermediates germane to gold-catalyzed enyne cycloaddition. Research activities are being pursued to fill these gaps and to develop an experimentally-grounded understanding of the mechanisms of gold pi-activation catalysis. The research is addressing four areas of inquiry: (1) the mechanisms of gold-catalyzed intermolecular hydrofunctionalization of carbon-carbon double bonds with strong and weak donor nucleophiles, (2) the extent of gold-carbon electron donation and d-to-pi backbonding in gold carbene complexes, (3) the structure and reactivity of cationic gold cyclopropyl carbene complexes lacking heteroatom stabilization, and (4) the mechanisms of silver-catalyzed hydroarylation and skeletal rearrangement of bicyclo-[3.2.0]-heptenes formed in gold-catalyzed enyne cycloaddition. Realization of the activities outlined in this proposal is expected to contribute in a meaningful way to the understanding of the mechanisms of gold(I)-catalyzed hydrofunctionalization and the structure and reactivity of gold carbene complexes.
