Monofluoromethyl Radical Mediated Halogen-Atom Transfer

Halogen-atom transfer (XAT) is an effective method for generating carbon radicals from alkyl halides. While stannanes and silanes have shown potential, their toxicity and secondary reactivity necessitate the search for better alternatives. Recently, carbon-based α-amino alkyl radicals have emerged as possible substitutes; however, their generation under photochemical conditions requires the use of photocatalysts. In this work, we present a novel XAT method that eliminates the need for photocatalysts by utilizing the direct excitation of a monofluoroacetoxy ligand-containing hypervalent iodine(III) reagent. This approach allows nucleophilic monofluoromethyl radicals to efficiently form carbon radicals from activated alkyl halides. These radicals can subsequently functionalize unactivated alkenes through atom transfer radical addition (ATRA). Our mechanistic studies provide insights into the generation of monofluoromethyl radical and its unique reactivity. This work highlights the untapped potential of simple, single carbon atom-containing radicals for effective alkyl radical generation.