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Guangbin Dong

Site-Selective C–C and C–H Functionalization of Common Functional Groups

Thu, Apr. 12, 2018, 4:30pm
Edward C. Taylor Auditorium, Frick B02
Host: Todd Hyster

C-H and C-C bonds are the most abundant bonds in majority of organic compounds. Selective functionalization of C-C and C-H bonds would lead to efficient synthesis of complex target molecules, but these transformations are generally of significant challenges. In the past, we have been focusing on a “cut and sew” strategy to synthesize bridged and fused rings by utilizing metal-catalyzed C-C bond activation of four-membered ketones. Driven by an objective to develop a “cut and sew” reaction with five-membered ring ketones, we obtained an unexpected discovery and later developed a regioselective ketone α-alkylation reaction using simple olefins. This reaction shows a broad substrate scope and high functional group tolerance, which can be further extended to the intramolecular transformation, a formal Conia-Ene reaction, as well as intermolecular alkenylation with alkynes. Meanwhile, driven by the need to improve the efficiency of the ketone alkylation reaction, we accidentally discovered an approach for catalytic C-C bond activation of cyclopentanones and some cyclohexanones, in which the proximal α C-C bond was cleaved and subsequently coupled with a β-aryl group through C-H activation. More recently, activation of the distal C-C bond in these unstrained ketones was enabled through using a bulkier catalyst system.