Reaktion #319315

Reaktionsgleichung

diazabicycloundecene

tetrahydrofuran

lithium chloride

(4S,5S)-3-benzyloxycarbonyl-4-isobutyl-5-formyl-2,2-dimethyloxazolidine

tetrahydrofuran

2-diethylphosphono-4-(tetrahydropyran-2-yloxy)pentanoic acid

tetrahydrofuran

tetrahydrofuran

→

ethyl 3-[(4S,5S)-3-benzyloxycarbonyl-4-isobutyl-2,2-dimethyloxazolidin-5-yl]-2-[2-(2-tetrahydropyranyloxy)-propyl]-2-pentenoate

Lösungsmittel

benzene

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThen, a solution prepared
2. 2
   workup.ADDITIONwas dropwise added
3. 3
   workup.STIRRINGThe mixture was stirred for 5 minutes
4. 4
   workup.STIRRINGThe mixture was stirred at room temperature for 10 minutes
5. 5
   SonstigeThen, a solution prepared
6. 6
   workup.ADDITIONwas gradually dropwise added
7. 7
   workup.STIRRINGThe mixture was stirred overnight at room temperature
8. 8
   FiltrationThen, after filtering
9. 9
   Sonstigeprecipitated inorganic salt off, the reaction solution
10. 10
    SonstigeThe reaction, solution
11. 11
    Einengenwas concentrated under reduced pressure
12. 12
    Sonstigea syrup thereby obtained
13. 13
    Waschenwashed sequentially with 50 ml of water and 50 ml of a saturated sodium chloride aqueous solution
14. 14
    Trocknendried over anhydrous magnesium sulfate
15. 15
    FiltrationAfter filtering the inorganic salt off, the filtrate
16. 16
    Einengenwas concentrated under reduced pressure
17. 17
    Sonstigea syrup thereby obtained
18. 18
    Sonstigewas purified by silica gel flash column chromatography (Kieselgel (E. Merck No. 9385), developer: hexane/ethyl acetate (10/1 ))
19. 19
    workup.ADDITIONThe fraction containing the desired product
20. 20
    Einengenwas concentrated
21. 21
    Sonstigedried under reduced pressure

Vorschrift

68 mg of lithium chloride was suspended in 5 ml of dry tetrahydrofuran under an argon stream. Then, a solution prepared by dissolving 0.53 g of 2-diethylphosphono-4-(tetrahydropyran-2-yloxy)pentanoic acid in 1.0 ml of dry tetrahydrofuran, was dropwise added thereto under stirring. The mixture was stirred for 5 minutes, and 0.55 ml of a dry tetrahydrofuran solution of diazabicycloundecene (1/1) was gradually added thereto. The mixture was stirred at room temperature for 10 minutes. Then, a solution prepared by dissolving 385 mg of (4S,5S)-3-benzyloxycarbonyl-4-isobutyl-5-formyl-2,2-dimethyloxazolidine in 2.0 ml of dry tetrahydrofuran, was gradually dropwise added thereto. The mixture was stirred overnight at room temperature. Then, after filtering precipitated inorganic salt off, the reaction solution was neutralized with 1N hydrochloric acid. The reaction, solution was concentrated under reduced pressure, and a syrup thereby obtained was dissolved in 50 ml of benzene, then washed sequentially with 50 ml of water and 50 ml of a saturated sodium chloride aqueous solution and then dried over anhydrous magnesium sulfate. After filtering the inorganic salt off, the filtrate was concentrated under reduced pressure, and a syrup thereby obtained was purified by silica gel flash column chromatography (Kieselgel (E. Merck No. 9385), developer: hexane/ethyl acetate (10/1 )). The fraction containing the desired product was concentrated and dried under reduced pressure to obtain 454 mg of ethyl 3-[(4S,5S)-3-benzyloxycarbonyl-4-isobutyl-2,2-dimethyloxazolidin-5-yl]-2-[2-(2-tetrahydropyranyloxy)-propyl]-2-pentenoate as a colorless transparent syrup.

Quelle