N-Fluoropyridinium triflate

A Useful Fluorinating Agent, N-Fluoropyridinium Triflate, and o-Fluorination of a Ketone... 

The difficulty of perfluorinating pyrrole is enhanced in the porphyrins, which have reduced 7r-density on the a-carbons. Although direct fluorination appears promising, it is not yet fully developed [88JCS(P1)1735 89CL263 90TL6847]. The use of N-fluoropyridinium triflate resulted only in meso-fluorination (92TL1069). 

N-Fluoropyridinium triflate is stable and can be stored indefinitely under a dry atmosphere. It slowly decomposes in water. The submitters report that it has a half-life of 13 days in D2O at room temperature. 

N-Fluoropyridinium triflate Pyridinium, 1-fluora-, salt with trifluoromethanesulfbnio acid (1 1) (12) (107263-95-6)... 

Several 2-substituted pyridines 73 can be prepared by reactions of N-fluoropyridinium triflate (72) with triethylamine in various solvents. A novel carbene has been proposed as the reactive species (87TL2705). Treatment of N-fluoropyridinium fluorides 74 with trinitromethane gives trinitromethyl-... 

Figure 7 1 Representative N-fluoro reagents, (a) H-tIuorotrifluoromethanesulfonimide. (b) N-fluoropyridinium triflate. (c) N-fluoro-o-benzenedisulfonimide (NFOBS). (d) Selectfluor -(BF4)2.

Umemoto T, Tomita K (1986) N-fluoropyridinium triflate and its analogs, the first stable 1 1 salts of pyridine nucleus and halogen atom. Tetrahedron Lett 27 3271-3274... 

Umemoto T, Tomita K, Kawada K (1990) N-fluoropyridinium triflate an electrophUic fluori-nating agent. In Paquette LA (ed) Organic syntheses, vol 69. WUey, New York, pp 129-143... 

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