Mechanistic Studies of C-C Bond Activation in Quinolinyl Ketones

Carbon-carbon single bonds form the framework for many organic molecules, but in most cases, they cannot be functionalized. Dreis and Douglas have reported the rhodium (I)-catalyzed isomerization of a quinolinyl ketone with an alkene tail to form a cyclized product, in a reaction that does involve carbon-carbon single bond activation (J. Am. Chem. Soc., 2009, 131, 412-413.). The Johnson lab hopes to understand the mechanism of this reaction in order to be better able to use C-C activation in organic synthesis. Currently, competition reactions are being used to study the relative rates of this reaction among substrates with electron-donating and electron-withdrawing groups substituted around the phenyl ring. From these experiments, inferences can be made about the reaction mechanism, specifically in relation to the rate-limiting step. Initial results suggest that the oxidative addition of the rhodium catalyst into the C-C bond is the slow step. Efforts are underway to prepare and cyclize an alkene-substituted substrate to further strengthen the mechanistic hypothesis