Selectfluor

Description

Selectfluor is a source of electrophilic fluorine. Selectfluor is very effective, safe, non-toxic, and easy to handle making it a convenient reagent for large scale synthesis. Historically electrophilic fluorinations were done using molecular fluorine (F2) which is very toxic and difficult to handle.

Description

1-ChloroMethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate)(Selectfluor) is a white solid (mp 190 °C), stable in air and to moisture. It is a dicationic salt soluble in cold water or dilute hydrochloric acid. However, it decomposes in dilute sodium hydroxide and reacts with cold DMSO (rapidly and exothermally) and with DMF (slowly on heating). It is moderately soluble in acetonitrile but only slightly soluble in lower alcohols and acetone, which makes the former the solvent of choice. Occasionally, reactions in these solvents were accelerated by adding a small amount of water or trifluoroacetic acid. Bulk quantities of Selectfluor should be stored in a cool, dry place and not heated above 80 °C. Fainzil’berg et al. have measured the reduction potentials of Selectfluor and other N-F compounds. With a positive reduction potential, E1/2 ) 0.33 V, Selectfluor is predicted to be a more reactive fluorinating reagent than, e.g., N-fluorobenzenesulfonimide, with E1/2 ) -1.24 V[1].

Chemical properties

White powder

The Uses of Selectfluor

Mild, versatile fluorinating reagent used in pharmaceutical and agricultural applications.

The Uses of Selectfluor

Effective electrophilic fluorinating reagent for a wide variety of substrates such as aromatics, alkenes, carbohydrates, etc.

General Description

This product is a fluorine donor also called Selectfluor and has been enhanced for catalysis.

Toxicology

1-ChloroMethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (F-TEDA-BF4) is moderately toxic (male rat oral LD50 640 mg kg?1; female rat 350–500 mg kg?1), and is an irritant to the eye and respiratory system. Always use approved dust mask (or respirator), gloves, and safety glasses when handling the solid. Carry out solubility tests on a sensible scale when seeking alternative solvents (note the problem with DMSO referred to above).

Advantages

As the advantages of non-toxicity, non-corrosion and chemical stability, 1-ChloroMethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) have been widely used in industry and public life.

References

[1] Rajendra P. Singh, Jean’ne M. Shreeve. “Recent Highlights in Electrophilic Fluorination with 1-Chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane Bis(tetrafluoroborate).” ChemInform 35 16 (2004).