Reaction #2028902

Reaction equation

THF

4-ethoxy-2,2′,3,3′-tetrafluorobiphenyl

sec-butyllithium

→

4-ethoxy-2,2′,3,3′-tetrafluorobiphenyl-4-carboaldehyde

Yield 70.0%

Solvents

N,N,-dimethylformamide

Conditions

Workup

1. 1
   Otherprepared by means of a conventional coupling reaction in a reaction vessel under an atmosphere of nitrogen
2. 2
   Temperaturethe reaction mixture was warmed slowly to room temperature
3. 3
   OtherThe reaction mixture was quenched with a saturated aqueous solution of ammonium chloride, and water (500 ml)
4. 4
   workup.ADDITIONwas added
5. 5
   Otherto give two layers
6. 6
   ExtractionThe water layer was extracted with toluene (200 ml) twice
7. 7
   Washthe combined organic layer was washed with water
8. 8
   Dryingdried over anhydrous magnesium sulfate
9. 9
   workup.DISTILLATIONThe solvent was distilled off under reduced pressure
10. 10
    workup.ADDITIONThe residue was treated with silica gel chromatography (silica gel: 30 g, eluent: toluene)

Procedure

THF (400 ml) was added to 4-ethoxy-2,2′,3,3′-tetrafluorobiphenyl (6) (39.25 g) prepared by means of a conventional coupling reaction in a reaction vessel under an atmosphere of nitrogen. The solution was cooled to −65° C. or lower, and sec-butyllithium (1.08 M in cyclohexane and n-hexane; 141.3 ml) was added dropwise. After the reaction mixture had been stirred at −65° C. for another 1 hour, N,N,-dimethylformamide (21.2 g) was added dropwise, and the reaction mixture was warmed slowly to room temperature. The reaction mixture was quenched with a saturated aqueous solution of ammonium chloride, and water (500 ml) was added to give two layers. The water layer was extracted with toluene (200 ml) twice, and the combined organic layer was washed with water and then dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure. The residue was treated with silica gel chromatography (silica gel: 30 g, eluent: toluene) to give 4-ethoxy-2,2′,3,3′-tetrafluorobiphenyl-4-carboaldehyde (7) (30 g) in 70% yield.

Source