Copper-mediated synthesis of mono- and dichlorinated diaryl ethers

An efficient synthesis of polychlorinated diphenyl ethers (PCDEs) using the Cu(OAc)2-catalyzed Chan-Lam coupling reaction is described. A library of all possible mono- and dichlorinated diphenyl ether congeners was prepared and characterized using MS, 1H, and 13C NMR spectroscopy, and Kovats retention indices. Our approach, using the optimized reaction conditions (i.e., reaction temperature, oxidizing atmosphere and base), significantly improves and simplifies the process compared to previously reported syntheses.