反应详情

Methyl 3-oxoicosanoate (5.2 g, 15.3 mmoles) is dissolved in anhydrous tetrahydrofuran (31 mL) and this solution is added slowly dropwise to an ice-cooled solution of lithium borohydride in anhydrous tetrahydrofuran (2 M, 31 mL, 61.2 mmoles). When the addition is complete, the cooling bath is removed and the reaction is stirred at ambient temperature for 16 hours. The clear, colorless solution is again cooled in an ice bath, and aqueous hydrochloric acid (1 M, 62 mL) is added slowly dropwise to decompose the excess reducing agent (gas is evolved). When a homogeneous solution is obtained, the mixture is concentrated to remove tetrahydrofuran. Methylene chloride (100 mL) is added; the mixture is shaken well and poured into a separatory funnel. The layers are allowed to separate and the bottom aqueous layer is drawn off. The aqueous layer is then washed once more with methylene chloride (100 mL), and the combined methylene chloride solutions are washed with saturated aqueous sodium chloride (50 mL). The methylene chloride solution is then dried over anhydrous sodium sulfate, filtered and co-evaporated five times with methanol (50 mL each) to dryness. The oil is dried well in vacuo. The yield is 3.7 g (77%).

1. additionWhen the addition
2. customthe cooling bath is removed
3. temperatureThe clear, colorless solution is again cooled in an ice bath
4. additionaqueous hydrochloric acid (1 M, 62 mL) is added slowly dropwise
5. customWhen a homogeneous solution is obtained
6. concentrationthe mixture is concentrated
7. customto remove tetrahydrofuran
8. additionMethylene chloride (100 mL) is added
9. stirringthe mixture is shaken well
10. additionpoured into a separatory funnel
11. customto separate
12. washThe aqueous layer is then washed once more with methylene chloride (100 mL)
13. washthe combined methylene chloride solutions are washed with saturated aqueous sodium chloride (50 mL)
14. dry with materialThe methylene chloride solution is then dried over anhydrous sodium sulfate
15. filtrationfiltered
16. customThe oil is dried well in vacuo