反应详情

To a stirred solution of ethyl 8-bromo-6-chloro-7-hydroxychroman-4-carboxylate (4.00 g, 11.9 mmol) and tert-butyl 4-fluoro-3-nitrobenzoate (3.16 g, 13.1 mmol) in N,N-dimethylformamide (66 mL) at ambient temperature was added solid potassium carbonate (2.64 g, 19.1 mmol). The resulting mixture was stirred in an oil bath set to 90° C. for 30 minutes. The mixture was cooled to ambient temperature and poured into a separatory funnel containing water (600 mL). Chloroform (300 mL) was added, followed by 1M hydrochloric acid (100 mL). The organic layer was dried over sodium sulfate and concentrated. The residue was purified by chromatography on silica gel, eluting with 90/10 hexanes/ethyl acetate to afford ethyl 8-bromo-7-(4-(tert-butoxycarbonyl)-2-nitrophenoxy)-6-chlorochroman-4-carboxylate as a light yellow glass (4.33 g, 65% yield).

1. additionpoured into a separatory funnel
2. dry with materialThe organic layer was dried over sodium sulfate
3. concentrationconcentrated
4. customThe residue was purified by chromatography on silica gel
5. washeluting with 90/10 hexanes/ethyl acetate