Hexane → HCID 53772504, compound

Temperature

-78 °C

n-Butyl lithium (a hexane solution with f=1.69, 20.7 ml) was dissolved in THF (57 ml), and the solution was cooled to -78° C. To this solution, a solution of diethylcarboxyfluoromethane phosphonate (3.48 g, 16.3 mmol) in THF (25 ml) was dropwise added at -78° C. The mixture was stirred at the same temperature for 30 minutes. To this reaction solution, a solution of 4-methoxycarbonylbutanal (2.11 g, 16.3 mmol) in THF (16 ml) was dropwise added at -78° C., and the mixture was stirred at the same temperature. One hour later, the cooling bath was removed, and the mixture was stirred at room temperature for further one hour. Then, the reaction solution was cooled to 0° C., and water (40 ml) was added thereto. The mixture was vigorously stirred. The separated organic layer was extracted with a saturated sodium hydrogencarbonate aqueous solution (20 ml×2), and the extract solutions were combined with the previous aqueous layer, and the mixture was washed with ethyl ether (40 ml×2). The aqueous layer was adjusted to pH 4 by using hydrochloric acid under cooling with ice, and then sodium chloride was added to saturation. Then, the mixture was extracted with ethyl ether (40 ml×3), and the organic layer was dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography (methylene chloride/acetone=4/1 (containing 0.1% of acetic acid)) to obtain 2-fluoro-6-methoxycarbonyl-2-hexenoic acid (2.34 g, a mixture of E- and Z-isomers, yield: 76%) as yellow oil.

1. stirringthe mixture was stirred at the same temperature
2. customOne hour later, the cooling bath was removed
3. stirringthe mixture was stirred at room temperature for further one hour
4. temperatureThen, the reaction solution was cooled to 0° C.
5. additionwater (40 ml) was added
6. stirringThe mixture was vigorously stirred
7. extractionThe separated organic layer was extracted with a saturated sodium hydrogencarbonate aqueous solution (20 ml×2)
8. washthe mixture was washed with ethyl ether (40 ml×2)
9. temperatureunder cooling with ice
10. additionsodium chloride was added to saturation
11. extractionThen, the mixture was extracted with ethyl ether (40 ml×3)
12. dry with materialthe organic layer was dried over anhydrous magnesium sulfate
13. distillationThe solvent was distilled off under reduced pressure
14. customthe residue was purified by silica gel column chromatography (methylene chloride/acetone=4/1 (containing 0.1% of acetic acid))

ORD record

ord-eecbe423d1704a30b3f5adb4d3b83ba5

Source dataset

uspto-grants-1990_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04906663