A practical and improved copper-catalyzed synthesis of the central intermediate of diafenthiuron and related products

A bioinspired Cu(I)/N-methylimidazole catalyst system is used for the synthesis of the diaryl ether part of diafenthiuron, a widely used insecticide. The convenient protocol proceeds smoothly with high selectivity and quantitative yield. Applying the optimized procedure various diaryl ether analogs are synthesized in good to excellent yield.