Screening of ligands for the Ullmann synthesis of electron-rich diaryl ethers

Abstract

In the search for new ligands for the Ullmann diaryl ether synthesis, permitting the coupling of electron-rich aryl bromides at relatively low temperatures, 56 structurally diverse multidentate ligands were screened in a model system that uses copper iodide in acetonitrile with potassium phosphate as the base. The ligands differed largely in their performance, but no privileged structural class could be identified.

Keywords

• catalysis
• C–O bond formation
• diaryl ethers
• nucleophilic aromatic substitution
• Ullmann-type coupling