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 β-sp(2) C-H bonds of benzoic acid derivatives and γ-sp(2) C-H bonds of α,α-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.