Microwave-Assisted/Pd-Catalyzed Regioselective Double C-N Arylations of 1,2,3-Triiodobenzene: Efficient and Unexpected Synthesis of N1,N2-Bis(2,3-diiodoaryl)benzene-1,2-diamines

Abstract

A simple, direct, and regioselective protocol to the synthesis of N1,N2-bis(2,3-diiodoaryl)benzene-1,2-diamines through highly regioselective microwave-assisted/palladium-catalyzed double C-N arylations of 1,2,3-triiodobenzene and benzene-1,2-diamine is reported. Remarkably, the C-N arylations proceeded bimolecularly at the terminal positions, the most active and less hindered position. This process was efficient and tolerated a wide range of substrates. The reaction of electron-rich/neutral 1,2,3-triiodoarene systems and electron-rich 1,2-diamines under the optimized conditions provided the highest isolated yields. This article describes a method for the first and unprecedented synthesis of tetra-iodinated N1,N2-diarylbenzene-1,2-diamine and iodinated 5,10-dihydrophenazine products that is regioselective and scalable and provides useful derivatives for other chemical reactions especially in the synthesis of new NHC ligands.