N-Arylation of nitrogen heterocycles with 2,4-difluoroiodobenzene

Arylation reactions of NH-heterocycles [specifically, pyrazole, 3-(trifluoromethyl)pyrazole, imidazole and pyrrole] with 2,4-difluoroiodobenzene in the absence and presence of copper catalysis are described. The combination of fluoro and iodo substituents in the same aryl substrate has facilitated both SNAr reactions at the C–F bonds and copper-catalysed Ullmann-type coupling reactions at the C–I bond. Products arising from regioselective reactions and multiple substitutions have been isolated, providing a range of new N-arylated pyrazole, imidazole and pyrrole derivatives.