TriMethyl(broModifluoroMethyl)silane

Colorless transparent liquid, initial boiling point 108℃, relative density 1.31 g/cm³.

Novel difluorocarbene source for the efficient difluoromethylenation of alkenes/alkynes and difluoromethylation of O-, S-, and N-nucleophiles.

Trimethyl(bromodifluoromethyl)silane can be used as neuroactive steroids.

As reported by Hu and co-workers, (Bromodifluoromethyl)trimethylsilane is a highly useful reagent for the formation of difluoromethene-containing 3-membered rings and can also difluoromethylate heteroatoms with the assistance of alkaline bases, most effectively KOH.

(1) Difluoromethylenation of TMSCN.

Ref. J. Org. Chem. 2012, 77, 58505855.
(2) Difluoromethylenation of benzyl and alkylzinc halides.

Ref. Org. Lett. 2013, 15, 917 – 919.
(3) Fluorination aminocarbonylation of aldehydes

Ref. Angew. Chem. Int. Ed. 2022, e202115467

(Bromodifluoromethyl)trimethylsilane (TMSCF₂Br) is commonly used as a source to generate dilfluorocarbene. TMSCF₃ (Ruppert–Prakash reagent) and BBr₃ undergoes fast halogen–exchange reaction to form MSCF₂Br.

A flask equipped with a reflux condenser was filled with NaBr (10.8 g, 105 mmol), 30% aqueous H2O2 solution (14.2 g, 125 mmol) and water (7 mL). The mixture was cooled in an ice/water bath and concentrated sulfuric acid (6.7 mL, 125 mmol) was added dropwise. The cooling bath was removed and TMSCHF2 (12.4 g, 100 mmol) was added to the resulting dark colored mixture. The reaction flask was immersed in a water bath at 40 C. and at this temperature was stirred under household incandescent bulb (75 ) W) irradiated and stirred until the bromine color almost disappeared (about 1 hour). The upper phase is separated, filtered through MgSO4 and distilled. Colorless liquid, yield 16.2 g, 80%.

[1]Angewandte Chemie International Edition.DOI :10.1002/anie.202283811
[2]The Journal of Organic Chemistry.DOI :10.1021/acs.orglett.2c02899