Trimethyloxonium tetrafluoroborate

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Trimethyloxonium tetrafluoroborate
Structural formula of trimethyloxonium tetrafluoroborate
Ball-and-stick models of the component ions of trimethyloxonium tetrafluoroborate
Names
IUPAC name
Trimethyloxonium tetrafluoroborate
Other names
Trimethyloxonium fluoborate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.006.360
Properties
C3H9BF4O
Molar mass 147.91 g·mol−1
Melting point 179.6–180 °C (355.3–356.0 °F; 452.8–453.1 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Trimethyloxonium tetrafluoroborate is the organic compound with the formula Me3OBF4. It is sometimes called the "Meerwein salt" after Hans Meerwein.[1]) This salt is a strong methylating agent, being a source of CH3+. It is a white solid. Triethyloxonium tetrafluoroborate is a closely related reagent.

Preparation and reactions[edit]

The compound is prepared by the reaction of boron trifluoride with dimethyl ether and epichlorohydrin:[1]

4 Me2O·BF3 + 2 Me2O + 3 C2H3(O)CH2Cl → 3 Me3O+BF
4
+ B[(OCH(CH2Cl)CH2OMe]3

The salt hydrolyzes readily:

Me3OBF4 + H2O → Me2O + MeOH + HBF4

Trimethyloxonium tetrafluoroborate is often ranked as the strongest reagent for the electrophilic methylation.[2]

References[edit]

  1. ^ a b T. J. Curphey (1988). "Trimethyloxonium Tetrafluoroborate". Org. Synth. ; Coll. Vol., 6, p. 1019 
  2. ^ Stang, Peter J.; Hanack, Michael; Subramanian, L. R. (1982). "Perfluoroalkanesulfonic Esters: Methods of Preparation and Applications in Organic Chemistry". Synthesis. 1982 (02): 85–126. ISSN 0039-7881. doi:10.1055/s-1982-29711.