反应详情

To a suspension of Mg turnings (0.231 g, 9.51 mmol) in diethyl ether (1.5 mL) was added a solution of 2-fluorobenzyl chloride (1.25 g, 8.65 mmol) in diethyl ether (9 mL) dropwise to the refluxing reaction mixture. The mixture was stirred for 10 min, cooled to room temperature and added dropwise to a solution of diethyl oxalate (2.53 g, 17.29 mmol) in diethyl ether (17 mL) at 0° C. The reaction mixture was stirred at room temperature for 2 hours, quenched with 1M aqueous hydrochloric acid and extracted with diethyl ether. The combined extracts were washed with brine, dried over magnesium sulfate, and concentrated under reduced pressure. The excess of diethyl oxalate was removed by bulb to bulb distillation at room temperature and the residue was purified by flash chromatography (SiO2, 15-20% ethyl acetate in petroleum ether) to give the resulting compound B4 as colorless oil in 70% yield which was used instantly in next step.

1. customdropwise to the refluxing reaction mixture
2. stirringThe reaction mixture was stirred at room temperature for 2 hours
3. customquenched with 1M aqueous hydrochloric acid
4. extractionextracted with diethyl ether
5. washThe combined extracts were washed with brine
6. dry with materialdried over magnesium sulfate
7. concentrationconcentrated under reduced pressure
8. customThe excess of diethyl oxalate was removed by bulb to bulb distillation at room temperature
9. customthe residue was purified by flash chromatography (SiO2, 15-20% ethyl acetate in petroleum ether)