CAREER: SusChEM: New Methods for Heterocycle Synthesis via Organic Photoredox Catalysis

In this project funded by the Chemical Synthesis Program of the NSF Chemistry Division, Professor David Nicewicz of The University of North Carolina at Chapel Hill is developing new and highly efficient chemical reactions for the synthesis of small cyclic organic molecules that have potential applications in therapeutics. Purely organic dyes that harvest visible light are used as catalysts in the development of these new and widely applicable synthetic transformations from readily available and renewable chemicals. The appropriate selection of these dyes and catalysts is improved by knowledge of the redox potentials associated with single electron redox chemistry. Dr. Nicewicz and his students are assembling and normalizing organic electrochemical redox data that will serve as a useful compendium of reference data for practitioners of organic, organometallic and inorganic chemistries. The broader impacts of this award also include public outreach to the Morehead Planetarium Science Center. Professor Nicewicz collaborates with Planetarium staff to design and develop 'The Chemistry of Cooking' targeted towards middle school students. The SciVentures Program focuses on the chemistries of emulsions, yeast and carbon dioxide, fermentation, and acids and bases exposing young people to the readily accessible chemistry concepts in the kitchen.

A novel two-component organic photooxidation catalyst system comprised of an acridinium salt and redox-active hydrogen atom donor enables several new classes of heterocycle-forming transformations. The classes of heterocycles forged by this method include cyclic ethers, lactones, pyrrolidines and lactams from alkenes and abundant chemical feedstocks such as unsaturated alcohols, carboxylic acids, amines and amides without the need for pre-functionalization. This metal-free dual catalyst system provides new tools to practioners of synthetic organic chemistry. The new reaction technology developed in this proposal is applied to the first total synthesis of the bisnortriterpenoid, rubriflordilactone B, a molecule with documented activity against HIV-1.