(Bromodifluoromethyl)trimethylsilane

Difluoromethylenation of alkynes: under a N₂ atmosphere, alkynes (0.5 mmol, 1.0 eq.), (bromodifluoromethyl)trimethylsilane (152 mg, 0.75 mmol, 1.5 eq.), tetrabutylammonium bromide (4.8 mg, 0.015 mmol, 0.03 eq.), and toluene (2.0 mL) are added into an oven-dried pressure tube at room temperature. After being heated at 110 °C for 2 h, the reaction mixture is cooled to rt and poured into a saturated Na₂CO₃ solution (5 mL), followed by extraction with Et₂O (2 × 15 mL). The organic layers are combined and dried over anhydrous K₂CO₃. After the removal of the solvents in vacuo, the residue is subjected to column chromatography (silica gel; petroleum ether : Et₃N = 40 : 1) to afford the desired products. [Note: these products are sensitive to acid, so the column must be eluted previously with petroleum ether : Et₃N = 10 : 1)].