反应详情

Dry tetrahydrofuran (60 ml) was cooled under nitrogen atmosphere to −50 to −60° C. 1M Lithium bis(trimethylsily)amide solution in hexane (56 ml, 56 mmol) was added. The temperature was kept at −50 to −60° C. and thiochroman-4-one was added dropwise over 20 min. Stirring was continued at low temperature for 60 min. Methyl cyanoformate (4.84 ml, 60.9 mmol) was added dropwise over 5 min to the reaction mixture. The obtained suspension was stirred at −50 to −60° C. for 80 min and then allowed to warm up to room temperature. Saturated ammonium chloride solution (100 ml) was added. The phases were separated, the aqueous phase extracted with ethyl acetate (2×100 ml). The combined organic phases were washed with water (50 ml), dried over magnesium sulphate, filtered and concentrated under vacuum. An orange oil was obtained and purified by column chromatography. The title compound was isolated as a yellow solid (4.70 g, 21.1 mmol, 42%). LCMS: m/z 221 [M−H]+.

1. customwas kept at −50 to −60° C.
2. stirringThe obtained suspension was stirred at −50 to −60° C. for 80 min
3. customThe phases were separated
4. extractionthe aqueous phase extracted with ethyl acetate (2×100 ml)
5. washThe combined organic phases were washed with water (50 ml)
6. dry with materialdried over magnesium sulphate
7. filtrationfiltered
8. concentrationconcentrated under vacuum
9. customAn orange oil was obtained
10. custompurified by column chromatography