Research Project
9964343
Project Summary New methods for the formation of carbon-carbon bonds are always at the forefront of organic reaction development. Of particular interest are those that require benign reagents, are atom-economical, and have low energy input. The projects detailed herein aim to develop new umpolung carbon-carbon bond forming reactions with visible-light mediated photocatalysis. Specifically, the projects seek to generate radical species by electron transfer to ketone-containing functional groups. This reactivity will be enabled by photocatalytic electron transfer either to or from an activated carbonyl species. Two specific goals will be approached: 1) Initial work will extend preliminary experimental results that have shown that ketyl radicals can be generated by the combined activity of photocatalysts and Lewis acids to enantioselective 1,4-additions with the use of chiral Lewis acids. 2) Electron transfer from 1,3-dicarbonyls is proposed to generate electrophilic radicals for carbon-carbon bond formation with nucleophiles. A variety of carbon-carbon bond forming reactions that involve 1,3-dicarbonyl radicals are proposed, including hydro-, amido-, and dialkylation of alkenes. In total, these new catalytic processes will provide highly efficient methods for the use of visible light to construct carbon-carbon bonds in complex and biologically relevant molecular settings. The achievement of the designed umpolung reactivity of carbonyl- containing compounds by single electron reduction or oxidation would broaden the scope of reactivity for these widely available reagents. As a result, this proposal will contribute to the general toolbox of carbon-carbon bond forming reactions with new methods that are able to simultaneously build molecular complexity and adjust oxidation state. The projects are specifically tailored to be carried out by a research team composed entirely of undergraduates and is therefore broken up into discrete individual projects. This proposal would enhance the research training and outcomes of a diverse group of undergraduates pursuing careers in the biomedical sciences.
