BF₃·Et₂O Functioning as a Fluorine Source in an PhIO mediated Intermolecular Aminofluorination

Zhang et al. have reported an intramolecular aminofluorination reaction of homoallylic amines to provide 3-fluoropyrrolidines. In this reaction, BF₃·Et₂O is used as a fluorine source with a hypervalent iodine (III) reagent PhIO as an oxidant and the reaction being carried out at room temperature. In this report, they demonstrate that BF₃·Et₂O plays dual roles of a PhIO activator to form a three membered iodonium ion intermediate and a fluorine source of a cyclic carbocation intermediate.