反应详情

To stirred mixture of ZnBr2 (40.0 g, 176 mmol, 5.44 equiv, 99%) in THF (100 mL) under nitrogen at 0° C. was added dropwise EtMgBr (60 mL, 3 M in THF). After 0.5 h at 0° C., the temperature was lowered to −78° C. and PdCl2(dppf) (3.72 g, 5.03 mmol, 0.16 equiv, 99%) was added followed by the dropwise addition of a solution of methyl 2,4-dibromobenzoate (compound 204.1, 10.0 g, 32.3 mmol, 1.00 equiv, 95%) in THF (200 mL). The reaction was stirred overnight at room temperature, then carefully quenched with water followed by HCl (aq., 1 M). The resulting mixture was extracted with 3×500 mL of ethyl acetate, and the combined organic layers were washed with 3×50 mL of brine, dried over anhydrous sodium sulfate, and concentrated in vacuo. The residue was purified using silica gel column chromatography with ethyl acetate/petroleum ether (1:60) as eluent to furnish 6.30 g (96%) of methyl 2,4-diethylbenzoate as a colorless oil

1. customwas lowered to −78° C.
2. stirringThe reaction was stirred overnight at room temperature
3. customcarefully quenched with water
4. extractionThe resulting mixture was extracted with 3×500 mL of ethyl acetate
5. washthe combined organic layers were washed with 3×50 mL of brine
6. dry with materialdried over anhydrous sodium sulfate
7. concentrationconcentrated in vacuo
8. customThe residue was purified