反应详情

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%)

1. customobtained
2. customobtained
3. temperaturewas heated
4. temperatureto reflux for 13 hours
5. filtrationSubsequently, after the catalyst was filtered off
6. extractionthe mixture was subjected to extraction with toluene
7. customthe organic layer thus obtained
8. washwas washed with water thrice
9. dry with materialdried over anhydrous magnesium sulfate
10. distillationThe solvent was distilled off under a reduced pressure
11. customthe residue thus obtained