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Reversal of the Regioselectivity of Iron-Promoted Hydrogenation and Hydrohalogenation of gem-Difluoroalkenes
We described an unprecedented iron-promoted hydrogen atom transfer (HAT) to gem-difluoroalkenes in reversed regioselectivity for the generation of difluoroalkyl radicals. Hydrogenation and halogenation of the in situ generated radicals gave difluoromethylated, chlorodifluoromethylated, bromodifluoromethylate and iododifluoromethylated products respectively. Mechanism experiments and theoretical studies revealed that the kinetic effect of the irreversible HAT process resulted in the reversal of the regioselectivity.
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