<scp>Photoredox‐Catalyzed Metal‐Free</scp> Regio‐ & Stereoselective C(sp<sup>2</sup>)–H Amination of Enamides with <scp><i>N</i>‐Aminopyridium</scp> Salts
Zheng‐Bao Qin, Kun Ni, Wang Li, Xiao‐Di Wu, Yu Zhang, Kai Zhao
Abstract
Comprehensive Summary A visible‐light‐induced photoredox‐catalyzed regioselective and stereoselective C(sp 2 )–H amination of enamides with bench‐stable and easily accessible N ‐aminopyridium salts is developed, affording synthetically and biologically prominent vicinal 1,2‐diamine scaffolds with broad substrate scope and excellent functional group compatibility. The transformation proceeded through a radical pathway involving the Giese addition of the relatively electrophilic N ‐centered sulfonamidyl radical species to nucleophilic β‐olefinic position of enamides followed by the ensuing single electron oxidation and β‐H elimination, delivering geometrically‐defined Z ‐configured β‐sulfonamidylated enamides. The operational simplicity, environmental friendliness and cost efficiency of this methodology allowed it to pave a new avenue to enrich the arsenal of synthetically crucial functionalized enamides and their related derivatives.