反应详情

温度

-70 °C

Compound (4a), 1.4 mmol, was dissolved in 3 mL of anhydrous dichloromethane under nitrogen. The temperature of the solution was lowered to −70° C. To the solution of (3) was added 455 mg (1.8 mmol) of boron tribromide (1.8 mL of a 1.0M boron tribromide in dichloromethane solution). The reaction mixture was stirred at −70° C. for one hour, followed by stirring at room temperature for three hours. The reaction progress was monitored by thin layer chromatography. The solution was then quenched with methanol at −70° C. and concentrated. A suspension of the concentrate was washed with 10% aqueous sodium bicarbonate solution. The organic phase was removed, washed with water and then brine (NaCl), dried over anhydrous magnesium sulfate, filtered, and concentrated under vacuum to give the crude product. Purification by flash chromatography on silica gel afforded the analytically pure product (5a): 1H NMR (300 MHz) (CDCl3): δ 7.44-6.76 (m, 8H), 5.58 (s, 1H), 2.66-2.61 (t, 2H), 1.71-1.66 (m, 2H), 1.40-1.34 (m, 6H), 1.00-0.95 (t, 3H).

1. customwas lowered to −70° C
2. stirringby stirring at room temperature for three hours
3. customThe solution was then quenched with methanol at −70° C.
4. concentrationconcentrated
5. additionA suspension of the concentrate
6. washwas washed with 10% aqueous sodium bicarbonate solution
7. customThe organic phase was removed
8. washwashed with water
9. dry with materialbrine (NaCl), dried over anhydrous magnesium sulfate
10. filtrationfiltered
11. concentrationconcentrated under vacuum
12. customto give the crude product
13. customPurification by flash chromatography on silica gel