Enabling Synthesis through Small Molecule Liberation

Dr. Jon Tunge of the University of Kansas will develop synthetic strategies that utilize the innate energy in molecules to enable new processes for safer chemical manufacturing. Specifically, methods will be developed that leverage the liberation of small stable molecules (carbon dioxide and/or hydrogen) from molecules that are derived from simple feedstocks that are often available from biomass byproducts of agriculture and forestry. The release of these small molecules, sometimes in combination with harvesting light energy, will provide the energy to drive chemical reactions without the need for traditional methods of energy input. It is anticipated that the methods developed will be applicable to advanced manufacturing via the synthesis of a wide variety of materials with potential applications as pharmaceutical agents, agrochemicals, and other substances of value to science, engineering, and commerce. The broader impacts of the funded project extend to the benefits accrued to society in outreach and educational activities designed to integrate the goals of this research with training and recruitment programs that incorporate and promote modern principles for the design of safer chemistry. A significant goal of these activities will be to engage in outreach to educate local K-12 students on common chemistry that occurs in their everyday environment and to connect these observables to contemporary challenges in material-efficient and energy-efficient chemistry. The funded project will focus on the development of chemical transformations based on the catalytic generation of reactive intermediates via the cleavage of C–C and C–H bonds. The catalytic pathways being developed will utilize release of small molecules to provide an efficient strategy for the formation of synthetically useful reactive intermediates directly from inexpensive carboxylic acids. The use of the hydrogen evolution reaction will allow atom-economical functionalization of biologically relevant materials like peptides and biomass-derived chemicals. These photochemical reactions will allow for the site-specific functionalization of molecules, providing new biomass-based routes for the synthesis of materials and pharmaceuticals. Additionally, strategies will be developed for the sequential and iterative coupling of readily-available, non-toxic, carboxylic acids. Performing these new transformations in series will allow construction of complex molecules through temporally- and kinetically-controlled iterative couplings that are expected to form the basis for next-generation automated synthesis. In total, the methods that will be developed will advance a general paradigm for synthetic chemists to use for accessing reactive species under mild conditions, while generating minimal waste. 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.