Copper-Catalyzed, Directing Group-Assisted Fluorination of Arene and Heteroarene C-H Bonds

We have developed a method for direct, copper-catalyzed, auxiliary-assisted fluorination of beta-sp(2) C-H bonds of benzoic acid derivatives and gamma-sp(2) C-H bonds of alpha,alpha-disubstituted benzylamine derivatives. The reaction employs a CuI catalyst, a AgF fluoride source, and DMF, pyridine, or DMPU solvent at moderately elevated temperatures. Selective mono- or difluorination can be achieved by simply changing reaction conditions. The method shows excellent functional group tolerance and provides a straightforward way for the preparation of ortho-fluorinated benzoic acids.