Efficient and Direct Route to 5-Iodo-4H-Quinoxalines via Copper-Catalyzed Double C-N Arylations of 1,2,3-Triiodoarenes: Potential Application towards 5-Substituted 4H-Quinoxalines

A simple, direct and regioselective protocol to substituted 5-iodo-4H-quinoxalines through domino double C-N arylations of 1,2,3-triiodobenzene and 1,2-diamines is reported. Remarkably, the N-arylation couplings proceeded unimolecularly at the vicinal positions, the most active and less hindered positions. This domino process tolerated a wide range of aromatic substrates. The reaction of electron-deficient 1,2,3-triiodoarene systems and DMEDA under the optimized conditions provided the highest isolated yields. The chemical transformation of the target compound, which serves as a valuable precursor in synthesis, was successfully demonstrated in the Suzuki-Miyaura reaction, giving the desired coupling derivatives with excellent isolated yields. This article describes a method for the first and unprecedented synthesis of 5-iodo-4H-quinoxalines that is regioselective, scalable, and provides useful derivatives for other chemical reactions.