Synthesis of diaryl ethers using an easy-to-prepare, air-stable, soluble copper(I) catalyst

We have found that bromo(triphenylphosphine)copper(I), an air-stable and soluble copper(I) complex, can be used as a catalyst in the synthesis of diaryl ethers. Using this catalyst, we have synthesized diaryl ethers from electron-rich aryl bromides and electron-rich phenols in the presence of cesium carbonate, in 17-24 h, in NMP. We also found that electron-deficient aryl bromides couple with phenols in the presence of cesium carbonate, in 6 h in NMP at 70 degreesC, without the catalyst.