Mild Conditions for Copper-Catalyzed Coupling Reaction of Phenols and Aryl Iodides and Bromides

Coupling of phenols and aryl bromides can be efficiently performed by means of catalytic amounts of copper iodide and the inexpensive ligand 1 (structure given in Table 1). The reaction is applicable to a wide range of substrates and proceeds at 60–80 °C, the lowest temperatures reported to date for an Ullmann‐type synthesis of diaryl ethers. Moreover, the use of aryl bromides and inexpensive K3PO4 as base make this method attractive for applications on an industrial scale.