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.

GRAPHICAL ABSTRACT

Keywords:

• Aryl halides
• Betti base
• copper
• phenol
• Ullmann coupling

Notes

^a Reaction conditions: iodobenzene (1.0 mmol), m-cresol (1.0 mmol), CuX (0.1 mmol), L (0.2 mmol), 2.0 equiv base, solvent (3 mL), 120 °C.

^b GC yield determined by using methoxybenzene as internal standard.

^c Reaction temperature is 80 °C.

^d Without L.

^a Reaction conditions: iodobenzene (1.0 mmol), phenol (1.0 mmol), CuI (0.1 mmol), L₁ (0.2 mmol), 2.0 equiv K₂CO₃, DMSO (3 mL), 120 °C. ^b Isolated yield.

^a Reaction conditions: aryl halides (1.0 mmol), m-cresol (1.0 mmol), CuI (0.1 mmol), L₁ (0.2 mmol), 2.0 equiv K₂CO₃, DMSO (3 mL), 120 °C.

^b Isolated yield.