Reaktion #65823

Reaktionsgleichung

chlorotrimethylsilane

(R)-3-[(bromoacetyl)oxy]tetradecanoic acid methyl ester

→

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

Ausbeute 22.5%

Lösungsmittel

Et2O

—

hexanes

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturat reflux
2. 2
   Filtrationsuction filtered through a coarse fritted funnel
3. 3
   Waschenwashing with 10 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 100 mL
9. 9
   ExtraktionH2O and extraction with 3×50 mL Et2O
10. 10
    WaschenThe combined organic layers were washed with 50 mL brine
11. 11
    Trocknendried over MgSO4
12. 12
    SonstigeThe Et2O was removed by rotary evaporation
13. 13
    Sonstigegiving 669 mg crude yellow solid
14. 14
    Filtrationfollowed by suction filtration through a medium fritted funnel
15. 15
    SonstigeThe product was dried under 25" vacuum at room temperature for 1.5 h

Vorschrift

In a flame-dried flask under N2 a mixture of 659 mg (10.1 mmol) zinc and 755 mg (1.99 mmol) (R)-3-[(bromoacetyl)oxy]tetradecanoic acid methyl ester in 10 mL 20% v:v Et2O:chlorotrimethylsilane was heated at reflux with rapid stirring for 20 min. The mixture was cooled to room temperature and suction filtered through a coarse fritted funnel, using a pad of celite, and washing with 10 mL Et2O. The homogenous filtrate was cooled in an ice/H2O bath and 10 mL tap H2O was added with stirring. After 10 min, the mixture was poured into 100 mL tap H2O and extraction with 3×50 mL Et2O was performed. The combined organic layers were washed with 50 mL brine and dried over MgSO4. The Et2O was removed by rotary evaporation giving 669 mg crude yellow solid. The solid was slurried in 9.0 mL hexanes for 30 min, followed by suction filtration through a medium fritted funnel. The product was dried under 25" vacuum at room temperature for 1.5 h, giving 120 mg (22%) (R)-5,6-dihydro-4-hydroxy-6-undecyl-2H-pyran-2-one as a white powder, mp=86°-7° C.

Quelle