Synthesis of unsymmetrical biaryl ethers through nickel-promoted coupling of polyfluoroarenes with arylboronic acids and oxygen

Abstract

Polyfluoro-substituted unsymmetrical biaryl ethers were synthesized via a novel Ni-catalyzed cross-coupling reaction of polyfluoroarenes with arylboronic acids and oxygen. The polyfluorinated arenes presumably captured the phenoxide intermediate efficiently, which made the oxygen-insertion proceed smoothly via the S_NAr protocol. The ¹⁸O labeling experiment demonstrated that the oxygen introduced into unsymmetrical diaryl ether originated from very trace amounts of oxygen in the reaction system. A plausible mechanism was also suggested.