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Primary hydroxy groups as in neopentyl alcohol 7 or neopentylglycol 18 react readily with perfluorobutanesulfonyl fluoride 1 in the presence of 2 equiv. of the nucleophilic 4-dialkylaminopyridines 4 to afford high yields of the corresponding N-alkyl-4-dialkylaminopyridinium perfluorobutanesulfonates (nonaflates). Secondary hydroxy groups give rise to a mixture of the corresponding olefins and monofluorides as well as of the corresponding N-alkyl-4-dialkylaminopyridinium nonaflates.

Perfluoroalkanesulfonyl fluorides (C n F 2n+1 SO 2 F) decompose slowly even at -20 °C in the presence of tertiary heteroaromatic or aliphatic amines to form the corresponding perfluorinated alkanes (C n F 2n+2 ) and amine-sulfur dioxide adducts.

5′-O-Trityl -thymidine reacts with excess perfluorobutanesulfonyl fluoride/DBU in toluene to 5′-O-trityl-2,3′-anhydrothymidine in 75% yield. Free thymidine gives rise to 4′,5′-dehydro-2,3′-anhydrothymidine and to 5′-fluoro-2,3′-anhydrothymidine. Dedicated to Professor Y. Mizuno on the occasion of his 7Sh birthday

Persilylation of excess D-ribose or D-glucose with 6-azauracil or N -benzoyladenine followed by condensation with trimethylsilyl triflate in acetonitrile at 80° affords the corresponding persilylated nucleosides. Transsilylation with methanol and chromatography on SiO2 give the pure free nucleosides in up to 70% yield.

The combination of n-perfluorobutanesulfonyl fluoride (2) with 1,8-diazabicyclo-[5.4.0]undec-7-ene efficiently converts primary and secondary alcohols in unpolar solvents into their corresponding fluorides.