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

To a stirred cooled (ice/salt, 0°) solution of carbon tetrabromide (48.82 g) in anhydrous CH2Cl2 (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 residual gum was poured into cyclohexane (1L) and stirred for 30 minutes. The organic phase was decanted and the residue taken up into CH2Cl2and poured into cyclohexane (1L). 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%).

1. additionwas added portionwise over 3 minutes
2. additionAfter the addition
3. stirringthe suspension was stirred at 0° for 1 hour
4. customthen quenched by the addition of water (75 ml)
5. customThe organic phase was separated
6. washwashed with brine (75 ml)
7. dry with materialdried (Na2SO4)
8. customevaporated to dryness
9. additionThe residual gum was poured into cyclohexane (1L)
10. stirringstirred for 30 minutes
11. customThe organic phase was decanted
12. additionpoured into cyclohexane (1L)
13. concentrationthe combined organic phases concentrated to ˜100 ml
14. concentrationThe filtrate was concentrated

ORD record

ord-f46320e289f14b8ba825b362d4da1059

Source dataset

uspto-grants-2005_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06861429B2