Reaktion #65821

Reaktionsgleichung

chlorotrimethylsilane

(R)-3-[(2-bromo-1-oxoocty)oxy]tetradecanoic acid phenyl ester

→

(R)-3-hexyl-5,6-dihydro-4-hydroxy-6-undecyl-2H-pyran-2-one

Ausbeute 67.3%

Lösungsmittel

Et2O

—

hexanes

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturat reflux
2. 2
   Filtrationsuction filtered through a coarse fritted funnel
3. 3
   Waschenwashing with 5 ml Et2O
4. 4
   TemperaturThe homogenous filtrate was cooled in an ice/H2O bath
5. 5
   workup.ADDITIONwas added
6. 6
   workup.STIRRINGwith stirring
7. 7
   workup.WAITAfter 10 min
8. 8
   workup.ADDITIONthe mixture was poured into 50 ml
9. 9
   ExtraktionH2O and extraction with 3×25 ml Et2O
10. 10
    WaschenThe combined organic layers were washed with 25 ml brine
11. 11
    Trocknendried over MgSO4
12. 12
    SonstigeThe Et2O was removed by rotary evaporation
13. 13
    Sonstigegiving a white solid
14. 14
    Filtrationfollowed by suction filtration through a medium fritted funnel
15. 15
    WaschenThe product was washed with 2.0 ml hexanes
16. 16
    Sonstigedried under 26" vacuum at room temperature for 1.5 h

Vorschrift

In a flame-dried flask under N2 a mixture of 336 mg (5.14 mmol) zinc and 510 mg (0.99 mmol) (R)-3-[(2-bromo-1-oxoocty)oxy]tetradecanoic acid phenyl ester in 5.0 ml 20% v:v Et2O:chlorotrimethylsilane was heated at reflux with rapid stirring for 20 minutes. The mixture was cooled to room temperature and suction filtered through a coarse fritted funnel, using a pad of celite, and washing with 5 ml Et2O. The homogenous filtrate was cooled in an ice/H2O bath and 5 ml tap H2O was added with stirring. After 10 min, the mixture was poured into 50 ml tap H2O and extraction with 3×25 ml Et2O was performed. The combined organic layers were washed with 25 ml brine and dried over MgSO4. The Et2O was removed by rotary evaporation, giving a white solid. The solid was stirred with 6.0 ml hexanes for 30 min, followed by suction filtration through a medium fritted funnel. The product was washed with 2.0 ml hexanes and dried under 26" vacuum at room temperature for 1.5 h, giving 235 mg (67%) (R)-3-hexyl-5,6-dihydro-4-hydroxy-6-undecyl-2H-pyran-2-one as a white powder, mp=109°-111° C.; [α]20D=-43.5° (1% in dioxane).

Quelle