Реакция #1008037

Уравнение реакции

1-(3-chloro-4-fluorophenyl)ethanone

ethyl 2,2-diethoxyacetate

LDA

→

(Z)-1-(3-Chloro-4-fluorophenyl)-4,4-diethoxy-3-hydroxybut-2-en-1-one

Растворители

THF

Условия реакции

Обработка

1. 1
   ДругоеThe resultant reaction mixture
2. 2
   Другоеto reach room temperature
3. 3
   ДругоеThe reaction was carefully quenched with water
4. 4
   workup.ADDITIONdiluted with EtOAc
5. 5
   ДругоеThe two layers were separated
6. 6
   Экстракцияthe aq. layer was extracted with EtOAc (2×150 mL) The combined organic layer
7. 7
   Промывкаwas washed with brine
8. 8
   Сушкаdried over anhydrous MgSO4
9. 9
   Фильтрацияfiltered
10. 10
    Концентрированиеthe filtrate was concentrated under reduced pressure
11. 11
    Другоеto provide a crude oil
12. 12
    ДругоеIt was purified by silica gel chromatography (1500 g Commodity column
13. 13
    Промывкаeluting with a 10% EtOAc in hexanes)
14. 14
    workup.ADDITIONFractions containing the product
15. 15
    Другоеevaporated
16. 16
    Другоеto afford Intermediate A39A (9.97 g, 35%) as a solid

Методика

To a −78° C. solution of 1-(3-chloro-4-fluorophenyl)ethanone (16.25 g, 94 mmol) and ethyl 2,2-diethoxyacetate (20.73 mL, 113 mmol) in THF (392 mL) was added, dropwise, a solution of LDA (51.8 mL, 104 mmol, 2M in THF). The resultant reaction mixture was gradually allowed to reach room temperature and continued stirring for 16 h. The reaction was carefully quenched with water and diluted with EtOAc. The two layers were separated and the aq. layer was extracted with EtOAc (2×150 mL) The combined organic layer was washed with brine, dried over anhydrous MgSO4, filtered and the filtrate was concentrated under reduced pressure to provide a crude oil. It was purified by silica gel chromatography (1500 g Commodity column, eluting with a 10% EtOAc in hexanes). Fractions containing the product were combined and evaporated to afford Intermediate A39A (9.97 g, 35%) as a solid. MS(ES): m/z=257 [M-OEt]+.

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