Decarbonylative Diaryl Ether Synthesis by Pd and Ni Catalysis.

Because diaryl ethers are present as an important motif in pharmaceuticals and natural products, extensive studies for the development of novel methods have been conducted. A conventional method for the construction of the diaryl ether moiety is the intermolecular cross-coupling reaction of aryl halides and phenols with a copper or palladium catalyst. We developed a catalytic decarbonylative etherification of aromatic esters using a palladium or nickel catalyst with our enabling diphosphine ligand to give the corresponding diaryl ethers. The present reaction can be conducted on gram scale in excellent yield. This reaction not only functions in an intramolecular setting but also allows for a cross-etherification using other phenols.