Cp*Co(III)-Catalyzed Coupling of Benzamides with α,β-Unsaturated Carbonyl Compounds: Preparation of Aliphatic Ketones and Azepinones.

A Cp*CoIII -catalyzed C-H functionalization of benzamide substrates with α,β-unsaturated ketones has been optimized, providing a facile route towards aliphatic ketone products. When employing α,β-unsaturated aldehydes as coupling partners, under the optimized protocol, a cascade reaction forming azepinones has also been developed. Finally, DFT studies have demonstrated how stabilization of a metallo-enol intermediate when employing α,β-unsaturated ketones is the driving force leading to the observed aliphatic ketone product rather than olefinic products reported using α,β-unsaturated esters as coupling partners.