N-Ethylacetonitrilium Tetrafluoroborate

[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.

Dehydration of Aldoximes.1

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

1. Ho, T.-L. S 1975, 401.
2. Meerwein, H.; Laasch, P.; Mersch, R.; Spille, J. CB 1956, 89, 209.
3. Blankespoor, R. L.; Doyle, M. P.; Smith, D. J.; Van Dyke, D. A.; Waldyke, M. J. JOC 1983, 48, 1176.
4. Ho, T.-L.; Wong, C. M. JOC 1973, 38, 2241.

Edwin C. Davison

University of Cambridge, UK

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