Electrophilic Fluorination with N – F Reagents

Abstract The synthesis of selectively fluorinated molecules is an important challenge in organic chemistry. This topic has received considerable attention because of the utility of fluorinated compounds in a wide variety of disciplines. There are three types of fluorination depending on whether the fluorine atom is radical, anionic, or cationic. Fluorine radicals are of little synthetic use because of the difficulties in controlling their reactivity. Fluorine is utilized in nucleophilic as well as electrophilic fluorinations Molecular fluorine is the simplest reagent of this type, however, its safe handling is difficult. Stable, selective reagents are crucial to the development of electrophilic fluorination. N‐F reagents have emerged as generally safer and easier to handle selective sources of electrophilic fluorine. N‐F reagents offer a range of fluorinating powers and some are available commercially. Two classes are known: neutral N‐F reagents and quaternary ammonium N‐F reagents (quaternary salts are usually the more powerful). N‐F reagents popularity arises because they posses a long shelf life, several are commercially available, and they can be handled safely in glassware. The drawback is the preferential use of molecular fluorine for their preparation. This article deals with the preparation and the use of all types of electrophilic fluorinating agents possessing the N‐F moiety.