CuI/Oxalamide Catalyzed Couplings of (Hetero)aryl Chlorides and Phenols for Diaryl Ether Formation

Couplings between (hetero)aryl chlorides and phenols can be effectively promoted by CuI in combination with an N‐aryl‐N′‐alkyl‐substituted oxalamide ligand to proceed smoothly at 120 °C. For this process, N‐aryl‐N′‐alkyl‐substituted oxalamides are more effective ligands than bis(N‐aryl)‐substituted oxalamides. A wide range of electron‐rich and electron‐poor aryl and heteroaryl chlorides gave the corresponding coupling products in good yields. Satisfactory conversions were achieved with electron‐rich phenols as well as a limited range of electron‐poor phenols. Catalyst and ligand loadings as low as 1.5 mol % are sufficient for the scaled‐up variants of some of these reactions.