Boron trifluoride etherate functioning as a fluorine source in an iodosobenzene-mediated intramolecular aminofluorination of homoallylic amines.

A widely used Lewis acid BF3·Et2O was shown to be capable of acting as an efficient fluorinating agent in an intramolecular aminofluorination reaction of homoallylic amines to provide 3-fluoropyrrolidines mediated by a commercially available hypervalent iodine(III) reagent PhIO at room temperature. A mechanism involving a carbocation intermediate was proposed on the basis of several experimental evidence.