Betti Base as an Efficient Ligand for Copper-Catalyzed Ullmann Coupling of Phenol with Aryl Halides

Abstract A simple, general, and highly efficient Betti base ligand has been developed for copper-catalyzed Ullmann coupling of phenol with aryl halides without the protection of an inert atmosphere. The reaction proceeds smoothly in the presence of K2CO3 as the base and dimethylsulfoxide as the solvent. The catalyst was reused several times with no evident loss of catalytic activity and is environmentally friendly.