Divergent regioselective Heck-type reaction of unactivated alkenes and N-fluoro-sulfonamides
Chunyang Zhao, Yang Li, Yujiao Dong, Miao Li, Dan Xia, Shuangqiu Gao, Qian Zhang, Qun Liu, Wei Guan, Junkai Fu
Abstract
The control of regioselectivity in Heck-type reaction of unactivated alkenes represents a longstanding challenge due to several detachable hydrogens in β-H elimination step, which generally afford either one specific regioisomer or a mixture. Herein, a copper-catalyzed intermolecular Heck-type reaction of unactivated alkenes and N-fluoro-sulfonamides with divergent regioselectivities is reported. The complete switch of regioselectivity mainly depends on the choice of different additives. Employment of alcohol solvent gives access to vinyl products, while the addition of carboxylate leads to the formation of allylic products. In addition, exclusion of these two promoting factors results in β-lactams via a C-N reductive elimination. This protocol shows a broad substrate scope for both alkenes and structurally diverse N-fluoro-sulfonamides, producing the corresponding products with excellent regio- and stereoselectivities. Further control experiments and DFT calculations provide in-depth insights into the reaction mechanism, highlighting the distinct effect of the additives on a bidentate auxiliary-stabilized Cu(III) intermediate.