Synthesis of Biaryl Ethers by the Copper-Catalyzed Chan-Evans-Lam Etherification from Benzylic Amine Boronate Esters

The copper-catalyzed etherification of ortho-borylated benzylic amines with phenols has been achieved to provide biaryl ethers that are prevalent in biologically active compounds. A variety of substitution patterns on the aryl boronate ester and the phenol are tolerated under the reaction conditions, providing moderate to high yields. A competition reaction between phenol and aniline revealed condition-dependent selectivity in which the phenol could be highly favored over the aniline.