Photoexcited Copper-Catalyzed Three-Component 1,4-Arylamination of 1,3-Dienes Using Aryl Thianthrenium Salts

Abstract The radical-type 1,2-carbofunctionalization of conjugated dienes is a robust regioselective approach to allylic amines. Nevertheless, the scope of available radical sources mainly focuses on Csp3-derived species. To date, the 1,4-arylamination of 1,3-dienes remains a challenging task, and there is also an urgent need for experimental and theoretical evidence to explain the regioselectivity of this reaction. Herein, we report a visible-light-driven, Cu-catalyzed 1,4-arylamination of 1,3-dienes that employs aryl thianthrenium salts as aryl radical precursors. This protocol enables the simultaneous formation of C−C and C−N bonds in a single operation, delivering a broad array of allylic amines with good functional-group tolerance and high regioselectivity. Experimental and computational mechanistic studies suggest that the in situ generated photoexcitable N-Cu(I) complex triggers aryl radical formation through a single-electron transfer process and addresses the issue of the regioselectivity of the reaction. This work provides a modular strategy for assembling allylic amines from simple dienes and expands the synthetic utility of thianthrenium salts in copper-mediated photochemical transformations.