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Iron-Catalyzed Halogen Exchange of Trifluoromethyl Arenes
preprintsubmitted on 19.02.2021, 02:48 and posted on 19.02.2021, 13:09 by Andreas Dorian, Emily Landgreen, Hayley Petras, James Shepherd, Florence Williams
We report the facile production of ArCF2X and ArCX3 from ArCF3 using catalytic iron(III)halides, which constitutes the first iron-catalyzed halogen exchange for non-aromatic CF bonds. Theoretical calculations suggest direct activation of C–F bonds by iron coordination. ArCX3 and ArCF2X products of the reaction are synthetically valuable due to their diversification potential. In particular, bromo-, chloro-, and iododifluoromethyl arenes (ArCF2Br, ArCF2Cl, ArCF2I, respectively) provide access to a myriad of difluoromethyl arene derivatives (ArCF2R). To optimize for mono-halogen exchange, a statistical method called Design of Experiments was used. Optimized parameters were successfully applied to electron rich and electron deficient aromatic substrates, and to the late stage diversification of flufenoxuron, a commercial insecticide.