[462-35-1] · C4H8BF4N · N-Ethylacetonitrilium Tetrafluoroborate · (MW 156.91)
(reagent for the dehydration of aldoximes to nitriles1)
Form Supplied in: needles; very unstable; not commercially available.
Preparative Methods: this salt can be prepared by N-alkylation of Acetonitrile with Triethyloxonium Tetrafluoroborate (eq 1),2 or by C-alkylation of isocyanides.1 The treatment of O,O,O-triethyl phosphorothioate with equimolar amounts of Nitrosonium Tetrafluoroborate in anhydrous acetonitrile gave the N-ethylacetonitrilium ion in moderate yield (eq 2).3
Handling, Storage, and Precautions: powerful alkylating agent similar to triethyloxonium tetrafluoroborate; treat with due caution.
Nitrilium salts are very electrophilic and react readily with hydroxylic substances. They react with aldoximes (in MeCN for 8 h at 20 °C, 0.5 h at 80 °C) to give imino esters, which collapse to give the amide of the nitrilium ion and a nitrile (eq 3).1 This reaction works well for a range of aromatic and alkyl R groups. The reagent compares favorably with the previous use of Trichloroacetonitrile for this transformation.4
Edwin C. Davison
University of Cambridge, UK