Reaktion #483087

Reaktionsgleichung

hydrochloric acid

trimethylchlorosilane

octanal

methyl 2-bromopropionate

→

Methyl 3-hydroxy-2-methyldecanoate

Lösungsmittel

ethyl acetate

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeAt room temperature, a three-necked flask fitted
2. 2
   Temperaturwith reflux condenser
3. 3
   TemperaturFollowing cooling to 60° C.
4. 4
   Temperaturthe temperature being maintained at 65° C. by external cooling
5. 5
   Temperaturafter cooling to 0° C.
6. 6
   workup.STIRRINGstirred for 30 min
7. 7
   SonstigeExcess zinc was removed by filtration
8. 8
   Sonstigethe organic phase separated
9. 9
   workup.STIRRINGThe organic phase was then stirred at 0° C. with 40 ml of 0.5 N hydrochloric acid
10. 10
    Waschenfinally washed with 20 ml of saturated sodium hydrogen carbonate solution
11. 11
    SonstigeFollowing phase separation
12. 12
    Trocknendrying over sodium sulfate
13. 13
    Sonstigethe solvent was removed by distillation under reduced pressure

Vorschrift

At room temperature, a three-necked flask fitted with reflux condenser, internal thermometer, dropping funnel and stirrer was charged, under nitrogen protective gas, with 5.5 g of zinc powder (84 mmol) in 34 ml of ethyl acetate. After 1.6 ml of trimethylchlorosilane (12.5 mmol) had been added, the mixture was heated at 65° C. Following cooling to 60° C., 7.2 g of octanal (56 mmol) were added, and over the course of 4 min, 11.2 g of methyl 2-bromopropionate (67 mmol) were added dropwise, the temperature being maintained at 65° C. by external cooling. The mixture was then stirred at 60° C. for 5 min and, after cooling to 0° C., acidified with 40 ml of 2 N hydrochloric acid to a pH of 1 and stirred for 30 min. Excess zinc was removed by filtration and the organic phase separated. The organic phase was then stirred at 0° C. with 40 ml of 0.5 N hydrochloric acid and finally washed with 20 ml of saturated sodium hydrogen carbonate solution. Following phase separation and drying over sodium sulfate, the solvent was removed by distillation under reduced pressure. Methyl 3-hydroxy-2-methyldecanoate was obtained in a yield of 10.2 g (85% of theory) with a boiling point of 68° C. (0.04 mbar). The diastereomer ratio was 2:1.

Quelle