反应详情

温度

0 °C

In a 250 mL round-bottomed flask was dissolved (S)-1,2-difluoro-3-(1-nitrohex-5-en-2-yl)-benzene (4.14 g, 17.2 mmol) in methanol (21 mL) under nitrogen. After cooling to 0° C., sodium methoxide (4.12 mL, 18.0 mmol) was added via syringe. After stirring at 0° C. for 30 min, the temperature was lowered to −60° C. Conc. sulfuric acid (2.93 mL, 54.9 mmol) in 21 mL methanol was added dropwise. The resulting milky mixture was stirred at −60 to −20° C. for 4 h. It was diluted with ethyl acetate and saturated ammonium chloride solution. The layers were separated. The aqueous layer was extracted with ethyl acetate (2×40 mL). The combined organic layers were washed with brine, dried, and concentrated to a give tan oil (4.8 g), which was dissolved in chloroform (124 mL) Water (31 mL) was added followed by slow addition of trifluoroacetic acid (31 mL). The mixture was stirred at rt overnight for 18 h. The layers were separated. The aqueous layer was extracted with methylene chloride. The combined organic layers were dried and concentrated to give a light yellow oil (5 g, 100%). This was directly carried onto next reaction immediately.

1. customwas lowered to −60° C
2. stirringThe resulting milky mixture was stirred at −60 to −20° C. for 4 h
3. customThe layers were separated
4. extractionThe aqueous layer was extracted with ethyl acetate (2×40 mL)
5. washThe combined organic layers were washed with brine
6. customdried
7. concentrationconcentrated to a give tan oil (4.8 g), which
8. dissolutionwas dissolved in chloroform (124 mL) Water (31 mL)
9. additionwas added
10. additionfollowed by slow addition of trifluoroacetic acid (31 mL)
11. stirringThe mixture was stirred at rt overnight for 18 h
12. customThe layers were separated
13. extractionThe aqueous layer was extracted with methylene chloride
14. customThe combined organic layers were dried
15. concentrationconcentrated