Triethyloxonium tetrafluoroborate, 95%, stab. with 3-5% diethyl ether

General References:

1. Trialkyloxonium salts, also known as Meerwein's salts, are powerful alkylating agents: Chem. Ber., 89, 209, 2060 (1956). For a brief feature on uses of Meerwein's salts in synthesis, see: Synlett, 195 (2004).
2. In combination with a hindered base, e.g. N-Ethyl diisopropyl amine, A11801, is a convenient reagent for the conversion of carboxylic acids to their ethyl esters by O-alkylation: Tetrahedron Lett., 4741 (1971); Org. Synth. Coll., 6, 576 (1988).
3. Secondary and tertiary amides are O-alkylated to give immonium salts and imino ethers, respectively. Reduction with borohydride provides an effective amide to amine conversion: Tetrahedron Lett., 61 (1968):
4. Likewise, N-alkylation of nitriles results in their activation to reduction by triethylsilane to give aldehydes, via the imines: Synthesis, 420 (1973); J. Chem. Soc., Chem. Commun., 45 (1974); J. Org. Chem., 46, 602 (1981).
5. For further reactions of trialkyloxonium salts, see Trimethyl oxonium tetrafluoroborate, A15175.
6. Landman, M.; Levell, T. J.; Conradie, M. M.; van Rooyen, P. H.; Conradie, J. Structural and conformational study of pentacarbonyl and phosphine substituted Fischer alkoxy-and aminocarbene complexes of molybdenum. J. Mol. Struct. 2015, 1086, 190-200.
7. Ammazzini, S.; Onor, M.; Pagliano, E.; Mester, Z.; Campanella, B.; Pitzalis, E.; Bramantia, D.; Ulivo, A. Determination of thiocyanate in saliva by headspace gas chromatography-mass spectrometry, followg a single-step aqueous derivatization with triethyloxonium tetrafluoroborate. J. Chromatogr. A 2015, 1400, 124-130.