Trimethyloxonium tetrafluoroborate (TMO), a trialkyloxonium salt, is a white salt at ambient temperature that can be added directly to reaction media to carry out the methylation of reactive, acidic analytes. The main drawback associated with the employment of TMO is the generation of tetrafluoroboric acid (HBF4), which may interfere with the analysis of acid-sensitive analytes and cause column degradation over time. However, the effects of this acid can be countered by neutralization with inorganic bases like sodium or potassium bicarbonate during the sample preparation step before instrument injection. This approach has proven crucially useful in analysing phosphonic and sulfonic acids related to organophosphorus-based nerve agents. TMO could be employed as a derivatizing agent in the methylation of a panel of environmentally relevant chlorinated phenols. It is also used in neutral and basic solutions for the selective methylation of the carboxyl groups of protohemin IX, hematohemin, and heme a[1-2].
This substance is a white to off-white crystals that is prone to water sensitivity and displays a level of hygroscopicity.
Trimethyloxonium Tetrafluoroborate is a trialkylated oxonium used as a methylation agent in organic synthesis. It is a reagent for the methylation of hydroxyl groups recently used in a complex, multistep synthesis directed towards spirastrellolide, a marine natural product.
Trimethyloxonium tetrafluoroborate act as a avmethylating agent and activates C-X multiple bonds. It is involved in the esterification of polyfunctional carboxylic acids. It acts as a catalyst in the polymerization of cyclic sulfides and ethers. Further, it is used in Beckmann rearrangement of oximes.
Trimethyloxonium Tetrafluoroborate is a potent alkylating agent, with its non-volatile nature reducing associated hazards. Nevertheless, it produces strong acids upon contact with water, so it is important to exercise caution and prevent water contact during its application.
[1] Carlos A Valdez, Roald N Leif, Edmund P Salazar. “Trimethyloxonium-mediated methylation strategies for the rapid and simultaneous analysis of chlorinated phenols in various soils by electron impact gas chromatography-mass spectrometry.” Scientific Reports (2022): 1401.
[2] R T Dean, D E Hultquist, L J DeFilippi. “Esterification of hemins with trimethyloxonium tetrafluoroborate.” Analytical biochemistry 76 l (1976): 1–8.
