反应详情

温度

-78 °C

A solution of 1,1-diisopropoxy-2,2,-dimethyl-3-pentanone (3.29 g) in 15 mL of THF is added slowly to a solution of lithium diisopropylamide (15.7 mmol) in 20 mL of THF cooled to −78° C., the mixture is stirred for 30 minutes, warmed to −40° C. and stirred for 30 minutes, then recooled to −78° C. A solution of (2S)-2-methyl-4-pentenal (16.36 mmol) in 2 mL of CH2Cl2 is added and the mixture is stirred for 1 hour at −78° C. Saturated aq. NH4Cl is added and the mixture is warmed to ambient temperature and extracted with ethyl acetate. The extract is dried over Na2SO4, filtered, and evaporated. The residue is purified by silica gel chromatography (2% ethyl acetate/hexanes) to separate the two diastereomeric products.

1. temperaturewarmed to −40° C.
2. stirringstirred for 30 minutes
3. customrecooled to −78° C
4. stirringthe mixture is stirred for 1 hour at −78° C
5. temperaturethe mixture is warmed to ambient temperature
6. extractionextracted with ethyl acetate
7. dry with materialThe extract is dried over Na2SO4
8. filtrationfiltered
9. customevaporated
10. customThe residue is purified by silica gel chromatography (2% ethyl acetate/hexanes)
11. customto separate the two diastereomeric products