S,O-Ligand Promoted meta-C–H Arylation of Anisole Derivatives via Palladium/Norbornene Catalysis

Reversing the conventional site-selectivity of C−H activation processes provides new retrosynthetic disconnections to otherwise unreactive bonds. Here, we report the realization of non-conventional site-selectivity through Pd/Norbornene cooperative-catalysis. Specifically, we report a new catalytic system based on Pd/norbornene with an S,O-ligand for the meta-C−H arylation of aryl ethers. Furthermore, we demonstrate the unique ability of this system to employ alkoxyarene substrates bearing both electron donating and withdrawing substituents. Additionally, ortho-substituted aryl ethers are well tolerated, with the ortho constraint overcome through the use of a novel norbornene mediator. Remarkably, the monoarylation of alkoxyarenes is achieved efficiently enabling the subsequent introduction of a second, different aryl coupling partner to rapidly furnish unsymmetrical terphenyls.