Reacción #409081

Ecuación de reacción

3-fluorobromobenzene

magnesium

trimethoxyborane

K2CO3

4-ethoxy-2,3-difluoroiodobenzene

hydrochloric acid

sec-butyl lithium

dihydroxy(3-fluorophenyl)borane

4-ethoxy-2,3-difluorobenzene

iodine

→

4-ethoxy-2,3,3′-trifluorobiphenyl

Rendimiento 86.2%

Disolventes

heptane toluene

toluene ethanol water

Condiciones de reacción

Tratamiento posterior

1. 1
   Otroobtained
2. 2
   Otroobtained
3. 3
   Temperaturawas heated
4. 4
   Temperaturato reflux for 13 hours
5. 5
   FiltraciónSubsequently, after the catalyst was filtered off
6. 6
   Extracciónthe mixture was subjected to extraction with toluene
7. 7
   Otrothe organic layer thus obtained
8. 8
   Lavadowas washed with water thrice
9. 9
   Secadodried over anhydrous magnesium sulfate
10. 10
    workup.DISTILLATIONThe solvent was distilled off under a reduced pressure
11. 11
    Otrothe residue thus obtained

Procedimiento

Mixture of 20.0 g (79.3 mmol) of 4-ethoxy-2,3-difluoroiodobenzene [obtained by lithiating 4-ethoxy-2,3-difluorobenzene with sec-butyl lithium and then reacting with iodine], 18.9 g (118.9 mmol) of dihydroxy(3-fluorophenyl)borane [obtained by reacting a Grignard reagent, which was prepared from 3-fluorobromobenzene and magnesium, with trimethoxyborane and then hydrolyzing with hydrochloric acid], 21.9 g (158.6 mmol) of K2CO3, 2.0 g of 5% Pd—C, and 100 ml of mixed solvent of toluene/ethanol/ water (1/1/1) was heated to reflux for 13 hours. Subsequently, after the catalyst was filtered off, the mixture was subjected to extraction with toluene, and the organic layer thus obtained was washed with water thrice and then dried over anhydrous magnesium sulfate. The solvent was distilled off under a reduced pressure and the residue thus obtained was subjected to silica gel column chromatography (eluent: heptane/toluene=8/2) to obtain 17.3 g of a crude 4-ethoxy-2,3,3′-trifluorobiphenyl. (Yield: 86.2%)

Fuente