Molar mass 354.26 g/mol Melting point 234 °C | Formula C7H14B2ClF9N2 Appearance colourless solid | |
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1-Chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) or Selectfluor, a trademark of Air Products and Chemicals, is a reagent in chemistry that is used as a fluorine donor. This compound is a derivative of the heterocycle DABCO . This colourless salt was first described in 1992 and has since been commercialized for use in organofluorine chemistry for electrophilic fluorination.
Contents
Preparation
Selectfluor is synthesized by the N-alkylation of diazabicyclo[2.2.2]octane (DABCO) with dichloromethane, followed by ion exchange with sodium tetrafluoroborate (replacing the chloride counterion for the tetrafluoroborate). Finally, this salt is treated with elemental fluorine and sodium tetrafluoroborate:
Applications
The conventional source of "electrophilic fluorine", i.e. the equivalent to the superelectrophile F+, is gaseous fluorine, which requires specialised equipment for manipulation. Selectfluor reagent is a salt, the use of which requires only routine procedures. Like F2, the salt delivers the equivalent of F+. It is mainly used in the synthesis of organofluorine compounds:
The ability of Selectfluor to transfer fluorine to alkyl radicals has recently been demonstrated.
Specialized applications
Selectfluor reagent also serves as a strong oxidant, a property that is useful in other reactions in organic chemistry. Oxidation of alcohols and phenols. As applied to electrophilic iodination, Selectfluor reagent activates the I–I bond in I2 molecule.