反应详情

温度

-15 °C

To a solution of 3,3-dimethyldihydrofuran-2(3H)-one (1 eq.) in ethanol (1 M) was added 8 N KOH (17 eq.). The mixture was stirred overnight, and the ethanolic solvent was concentrated in vacuo. To the remaining aqueous solution was added ethyl acetate and cooled to −15° C. Concentrated HCl was added dropwise until pH<1, taking care the internal temperature does not exceed 10° C. The aqueous layer was extracted with ethyl acetate three times. The combined organic extracts were dried over anhydrous Na2SO4, filtered, and cooled in an ice water bath. A solution of diazomethane in ether was added until a yellow color persisted. The reaction was stirred for an additional 10 min at rt and then concentrated in vacuo. The crude product was purified by flash column chromatography (SiO2, 10 to 60% EtOAc in Hex) to afford the title compound as an oil.

1. concentrationthe ethanolic solvent was concentrated in vacuo
2. additionTo the remaining aqueous solution was added ethyl acetate
3. additionConcentrated HCl was added dropwise until pH<1
4. customdoes not exceed 10° C
5. extractionThe aqueous layer was extracted with ethyl acetate three times
6. dry with materialThe combined organic extracts were dried over anhydrous Na2SO4
7. filtrationfiltered
8. temperaturecooled in an ice water bath
9. additionA solution of diazomethane in ether was added until a yellow color
10. stirringThe reaction was stirred for an additional 10 min at rt
11. concentrationconcentrated in vacuo
12. customThe crude product was purified by flash column chromatography (SiO2, 10 to 60% EtOAc in Hex)