Copper-Catalyzed C-O Bond Formation between Diaryliodonium Salts and Chelating Alcohols

We report a copper-catalyzed C-O bond formation using diaryliodonium salts and chelating alcohols. Our protocol operates efficiently under very mild reaction conditions, such as base-free, room temperature, and short reaction time, and uses only 2 mol % Cu₂O without any additional ligands. These features represent a significant advancement over previous methods, which typically require strong bases, high temperature, and/or additional ligands. Various diaryliodonium salts react in high yields with a broad range of diols under our developed conditions. Furthermore, other chelating alcohols, such as β-heteroatom-functionalized alcohols, are also effective at room temperature or slightly higher temperature. This method provides a useful tool for the practical synthesis of aryl alkyl ethers.