反应详情

To a stirred solution of ethyl 8-bromo-7-(4-(tert-butoxycarbonyl)-2-nitrophenoxy)-6-chlorochroman-4-carboxylate (Example 106, Step B) (0.59 g, 1.05 mmol) in toluene (6 mL) was added successively water (0.3 mL), potassium phosphate (0.67 g, 3.2 mmol), tricyclohexylphosphine (0.12 g, 0.42 mmol), and cyclopropylboronic acid (0.18 g, 2.1 mmol). The resulting mixture was stirred and a balloon of nitrogen with a three-way purge valve was attached, and the flask was evacuated and refilled five times with nitrogen. Palladium(II) acetate (0.047 g, 0.21 mmol) was added, and again the flask was evacuated and refilled five times with nitrogen. The mixture was stirred in an oil bath set to 100° C. under the nitrogen balloon for 1.5 hours. The mixture was cooled to ambient temperature, and diluted with ethyl acetate (25 mL) and water (15 mL). The organic layer was dried over sodium sulfate and concentrated. The residue was purified by chromatography on silica gel, eluting with 85/15 hexanes/ethyl acetate, to afford the desired compound as a yellow oil (0.28 g, 51%).

1. customa balloon of nitrogen with a three-way purge valve
2. customthe flask was evacuated
3. additionrefilled five times with nitrogen
4. customagain the flask was evacuated
5. additionrefilled five times with nitrogen
6. stirringThe mixture was stirred in an oil bath
7. additiondiluted with ethyl acetate (25 mL) and water (15 mL)
8. dry with materialThe organic layer was dried over sodium sulfate
9. concentrationconcentrated
10. customThe residue was purified by chromatography on silica gel
11. washeluting with 85/15 hexanes/ethyl acetate