Development of N-F fluorinating agents and their fluorinations: Historical perspective

This review deals with the historical development of all N -F fluorinating agents developed so far. The unique properties of fluorine make fluorinated organic compounds attractive in many research areas and therefore fluorinating agents are important. N -F agents have proven useful by virtue of their easy handling. This reagent class includes many types of N -F compounds: perfluoro- N -fluoropiperidine, N -fluoro-2-pyridone, N -fluoro- N -alkylarenesulfonamides, N -fluoropyridinium salts and derivatives, N -fluoroquinuclidium salts, N -fluoro-trifluoromethanesulfonimide, N -fluoro-sultams, N -fluoro-benzothiazole dioxides, N -fluoro-lactams, N -fluoro- o -benzenedisulfonimide, N -fluoro-benzenesulfonimide, 1-alkyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane salts, N -fluoropyridinium-2-sulfonate derivatives, 1-fluoro-4-hydroxy-1,4-diazoniabicyclo[2.2.2]octane salts, N -fluorodinitroimidazole, N -fluoro-trichloro-1,3,5-triazinium salt, N -F ethano-Tröger’s base derivatives, N -fluoro-methanesulfonimide, N -fluoro- N -arylarenesulfonamides, bis N -F salts such as N , N’ -difluorobipyridinium salts and N , N’ -difluoro-1,4-diazoniabicyclo[2.2.2]octane salts, and their many derivatives and analogs, including chiral N -F reagents such as optically active N -fluoro-sultam derivatives, N -fluoro-alkaloid derivatives, DABCO-based N -F derivatives, and N -F binaphthyldisulfonimides. The synthesis and reactions of these reagents are described chronologically and the review also discusses the relative fluorination power of each reagent and their mechanisms chronicling developments from a historical perspective.