A General Method for Copper-Catalyzed Arylation of Arene C-H Bonds

A general method for copper-catalyzed arylation of sp(2) C-H bonds with pK(a)'s below 35 has been developed. The method employs aryl halide as the coupling partner, lithium alkoxide or K3PO4 base, and DMF, DMPU, or mixed DMF/xylenes solvent. A variety of electron-rich and electron-poor heterocycles such as azoles, caffeine, thiophenes, benzofuran, pyridine oxides, pyridazine, and pyrimidine can be arylated. Furthermore, electron-poor arenes possessing at least two electron-withdrawing groups on a benzene ring can also be arylated. Two arylcopper-phenanthroline complex intermediates were independently synthesized.