Reaction #2139945

Reaction equation

carbon dioxide

LDA

4-bromo-2-fluorotoluene

hydrochloric acid

→

6-bromo-2-fluoro-3-methylbenzoic acid

Yield 49.2%

Solvents

THF

THF

Conditions

Workup

1. 1
   Extractionthe solution was extracted with MTB ether
2. 2
   Washthe combined organic phases were washed with water
3. 3
   Dryingdried over sodium sulfate
4. 4
   Otherevaporated under reduced pressure
5. 5
   OtherCrystallisation of the crude product from 1-chlorobutane

Procedure

50 ml (0.385 mol) of 4-bromo-2-fluorotoluene were dissolved in 750 ml of THF, and 231 ml (0.462 mol) of a 2 M solution of LDA in THF were added dropwise at −70° C. After 70 minutes, 37.2 g (0.846 mol) of carbon dioxide were passed in, and the batch was allowed to thaw. After acidification using conc. hydrochloric acid, the solution was extracted with MTB ether, and the combined organic phases were washed with water, dried over sodium sulfate and evaporated under reduced pressure. Crystallisation of the crude product from 1-chlorobutane gave 44.1 g (49%) of 6-bromo-2-fluoro-3-methylbenzoic acid as white crystals.

Source