Reaction #1277

Reaction equation

3,4-difluorobromobenzene

water

4-(4-propylcyclohexyl)-phenyltrimethoxysilane

TBAF

→

white crystals

Yield 94.5%

4-(4-propylcyclohexyl)-3',4'-difluorobiphenyl

Yield 94.5%

Solvents

toluene

toluene

toluene

Conditions

Workup

1. 1
   OtherAfter the solvent was removed under reduced pressure
2. 2
   TemperatureThe resulting mixture was refluxed for 3 hours
3. 3
   TemperatureAfter cooling, to the reaction mixture
4. 4
   OtherThe organic layer was separated
5. 5
   Extractionthe aqueous layer was extracted with toluene three times
6. 6
   DryingThe combined organic layer was dried over magnesium sulfate
7. 7
   OtherAfter the magnesium sulfate was removed by filtration
8. 8
   Otherthe filtrate was evaporated under reduced pressure
9. 9
   OtherThe residue was purified by silica gel column chromatography (heptane)

Procedure

To 0.645 g (2 mmol) of 4-(4-propylcyclohexyl)-phenyltrimethoxysilane (Ih) was added 2.1 ml of TBAF (2.1 mmol, 1M in THF) under nitrogen, and the mixture was stirred at room temperature for 30 minutes. After the solvent was removed under reduced pressure, a solution of 3,4-difluorobromobenzene (0.463 g, 2.4 mmol) in toluene (1 ml) was added, followed by the addition of a suspension of tetrakis(triphenylphosphine)palladium(0) (0.116 g, 0.1 mmol) in toluene (3 ml). The resulting mixture was refluxed for 3 hours. After cooling, to the reaction mixture were added water and toluene. The organic layer was separated and the aqueous layer was extracted with toluene three times. The combined organic layer was dried over magnesium sulfate. After the magnesium sulfate was removed by filtration, the filtrate was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (heptane) to obtain 0.594 g (40%) of white crystals.

Source