Saturday, November 23, 2024
11/23/2024
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 utilize benign reagents, are atom-economical, and have low energy input. The projects detailed herein will develop new umpolung carbon-carbon bond forming reactions with visible-light mediated photocatalysis. Specifically, the projects seek to generate radical species by electron transfer with 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 titanium complexes to react unactivated ketones and enones; and 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 ketyl and 1,3-dicarbonyl radicals are proposed, including homoaldol additions, enantioselective hydroalkylation, and oxidative enolate heterocoupling. 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 are therefore divided 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.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).
