Carbon tetrabromide → 4-Bromo-1-(bromomethyl)-2-(trifluoromethyl)benzene

Participants

Reaction Steps

Treat a mixture of 4-bromo-2-(trifluoromethyl)benzaldehyde (6.52 g, 25.8 mmol) and methanol (250 mL) in a 500 mL flask with sodium borohydride (778 mg, 20.6 mmol). Stir the reaction at room temperature for 1 hour then dilute with ethyl acetate (300 mL). Wash with water (2×200 mL) and saturated sodium chloride solution (1×200 mL), then dry over anhydrous magnesium sulfate. After filtering, concentrate the solution under vacuum to dryness. Add dimethylformamide (250 mL) to the residue and cool in an ice bath before treating with carbon tetrabromide (12.78 g, 38.5 mmol) and triphenylphosphine (10.11 g, 38.5 mmol) for 3 hours. Add ethyl acetate (300 mL) and wash with water (2×200 mL) then saturated sodium chloride solution (1×200 mL). Dry over anhydrous magnesium sulfate and concentrate under vacuum. Purify the crude product via silica gel chromatography eluting with hexanes to afford 6.02 g (74%) of the product as a clear oil: 1H NMR (300 MHz, CDCl3) δ 7.78 (d, 1H, J=1.9 Hz), 7.68 (dd, 1H, J=1.9 Hz, J=8.3 Hz), 7.47 (d, 1H, J=8.3 Hz), 4.57 (s, 2H).

Provenance & Evidence