Réaction #65817

Équation de réaction

H2O

methyl (R)-3-hydroxytetradecanoate

2-bromooctanoyl chloride

pyridine

→

(R)-3-[(2-bromo-1-oxooctyl)oxy]tetradecanoic acid methyl ester

Rendement 87.4%

Solvants

—

hexanes

CH2Cl2

Conditions de réaction

Traitement

1. 1
   workup.ADDITIONwas poured into a separatory funnel
2. 2
   workup.ADDITIONcontaining
3. 3
   workup.ADDITIONa mixture of 200 mL
4. 4
   workup.STIRRINGThis mixture was shaken
5. 5
   Autrethe layers separated
6. 6
   ExtractionThe aqueous layer was extracted with 2×100 mL ether
7. 7
   LavageThe combined ether layers were washed with 200 mL brine, and 3×200 mL H2O
8. 8
   SéchageThe ether was dried over MgSO4
9. 9
   Autreremoved by rotary evaporation
10. 10
    Autregiving 8.95 g crude product
11. 11
    Filtrationsuction filtered through a 1" pad of silica gel 60 in a 60 mL coarse sintered glass funnel
12. 12
    Lavagewashing with 150 mL CH2Cl2
13. 13
    AutreRotary evaporation

Mode opératoire

To a rapidly-stirred slurry of 5.18 g (20.0 mmol) methyl (R)-3-hydroxytetradecanoate and 5.03 g (20.8 mmol) 2-bromooctanoyl chloride in 100 mL hexanes at 0° C. in a flame-dried flask under N2 was added 1.67 mL (20.6 mmol) pyridine all at once. After stirring for 10 minutes the cloudy white mixture was poured into a separatory funnel containing a mixture of 200 mL tap H2O/100 mL ether. This mixture was shaken and the layers separated. The aqueous layer was extracted with 2×100 mL ether. The combined ether layers were washed with 200 mL brine, and 3×200 mL H2O. The ether was dried over MgSO4 and removed by rotary evaporation, giving 8.95 g crude product. This yellow oil was dissolved in 30 mL CH2Cl2 and suction filtered through a 1" pad of silica gel 60 in a 60 mL coarse sintered glass funnel, washing with 150 mL CH2Cl2. Rotary evaporation gave 8.10 g (87%) (R)-3-[(2-bromo-1-oxooctyl)oxy]tetradecanoic acid methyl ester as a yellow oil. The oil was found to be suitable for use in the cyclization reaction producing the lactone of Example 5. Analytically pure samples could be prepared by subjecting the oil to radial chromatography, eluting with CH2Cl2.

Source