Carbon tetrabromide → 1-(2,2-Dibromoethenyl)-3-fluorobenzene

Participants

Reaction Steps

To a stirred, cooled (ice/salt, 0°) solution of carbon tetrabromide (48.82 g) in anhydrous DCM (200 ml) was added, portionwise over 3 minutes, triphenylphosphine (77.1 g), maintaining the temperature below 10°. The resulting orange suspension was stirred at 0° for 1 hour before adding to it 3-fluorobenzaldehyde (7.8 ml). After the addition was complete, the suspension was stirred at 0° for 1 hour then quenched by the addition of water (75 ml). The organic phase was separated and washed with brine (75 ml), dried (Na2SO4) and evaporated to dryness. The residue was poured into cyclohexane (1 L) and stirred for 30 minutes. The organic phase was decanted and the residue taken up into DCM and poured into cyclohexane (1 L). This procedure was repeated twice more and the combined organic phases concentrated to ˜100 ml and passed through silica gel. The filtrate was concentrated to give the title compound as a mobile yellow oil (24 g, 100%). MH+ 280, MH− 279

Provenance & Evidence