Mechanistic Investigations of Alkene Carboacylation via C-C Bond Activation in Quinolinyl Ketones
Dr. Jeffrey Johnson, Hope College
Carbon-carbon single bonds form the framework for many organic molecules, but in most cases, they cannot be functionalized. This presentation will summarize the mechanistic investigation of the rhodium-catalyzed intramolecular carboacylation of an alkene, proposed to proceed through carbon-carbon bond activation. A kinetic analysis revealed an unusual first order rate law with no rate dependence upon substrate. Additional experiments identified the catalytic resting state, while determining activation parameters and 12C/13C kinetic isotope effects. Additional studies indicated that electron-donating groups increased the rate of reaction. This conclusion is consistent with the kinetics of the parent compound, as electron-donating substituents would be expected to stabilize the high-energy, electron-deficient intermediate of the rate-limiting C-C insertion step. A related mechanistic investigation with a second rhodium catalyst has revealed a similar but distinct mechanism. The combined insight from these studies promises to guide the development of new carbon-carbon single bond activation methodologies.
A recommended citation will become available once a downloadable file has been added to this entry.