反应详情

To a mixture of zinc (23.1 g; 353.9 mmol) in anhydrous diethyl ether (400 mL) was added trimethylsilyl chloride (0.5 mL). The mixture was stirred for 15 minutes at room temperature and refluxed. Bromoacetic acid tert-butyl ester (56.5 g, 290.0 mmol) was added dropwise and the reaction continued refluxing for an additional 1 hour. The mixture was then cooled to room temperature and cannulated to a solution of 1-(2,3-dimethoxy-pyridin-4-yl)-propan-1-one (13.8 g; 70.8 mmol) in anhydrous tetrahydrofuran (300 mL). The reaction was stirred for 16 hours at room temperature and quenched with saturated ammonium chloride solution. The aqueous layer was extracted with dichloromethane. The combined extracts were dried over sodium sulfate and concentrated under reduced pressure and purified by chromatography (SiO2; 2-10% ethyl acetate/hexane) to give the product 3-(2,3-dimethoxy-pyridin-4-yl)-3-hydroxy-pentanoic acid tert-butyl ester (6) (16.0 g).

1. temperaturerefluxed
2. temperaturethe reaction continued refluxing for an additional 1 hour
3. temperatureThe mixture was then cooled to room temperature
4. stirringThe reaction was stirred for 16 hours at room temperature
5. customquenched with saturated ammonium chloride solution
6. extractionThe aqueous layer was extracted with dichloromethane
7. dry with materialThe combined extracts were dried over sodium sulfate
8. concentrationconcentrated under reduced pressure
9. custompurified by chromatography (SiO2; 2-10% ethyl acetate/hexane)