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.

Reactions performed under basic conditions with and without copper catalysis yield a variety of N-arylated pyrazole, imidazole and pyrrole derivatives: regioselectivity and multiple additions have been observed.Figure optionsDownload as PowerPoint slide