Ligand‐Free Pd‐Catalyzed Direct C‐H Arylation of Polyfluoroarenes with Aryl Iodides under Ambient Air Conditions

We report the synergistic use of Pd(OAc)₂ and Ag₂O for the direct C−H arylation of polyfluoroarenes with aryl iodides in DMF as the solvent. This method is straightforward, can be conducted in air, and does not require additional ligands, yielding fluorinated unsymmetrical biaryl products in up to 99 %. Experimental studies and DFT calculations suggest that the formation of [(DMF)₂Pd^II(C₆F₅)₂] in DMF as a coordinating solvent does not inhibit the reaction, as the Pd complex reacts with aryl iodides by oxidative addition upon dissociation of a single DMF ligand to form [(DMF)Pd^IV(C₆F₅)₂(Ar)(I)] before the desired arylation product is released. This contrasts with our previous report on the nucleophilic coupling between C₆F₅H and aryl‐Bpin, in which the formation of [(DMF)₂Pd^II(C₆F₅)₂] was found to halt the reaction.