Visible Light-Induced Radical Cascade Functionalization of Quinoxalin-2(1)-ones: Three-Component 1,2-Di(hetero)arylation Approach with Styrenes and Thianthrenium Salts.

The additive-free visible light-induced three-component 1,2-di(hetero)arylation of styrenes was developed using quinoxalin-2(1)-ones and thianthrenium salts. The purple visible light excitable quinoxalin-2(1)-ones were utilized for the single-electron transfer to aryl thianthrenium salts, where the generated aryl radical species underwent the addition cascade to styrenes and quinoxalin-2(1)-ones. The direct aryl radical addition to quinoxalin-2(1)-ones also led to the formation of a side product, C3-aryl quinoxalin-2(1)-ones, capable of a photoredox process to help the formation of 1,2-di(hetero)arylation products.