反应详情

温度

-20 °C

Under a nitrogen atmosphere, 40.4 g of ethyl dibromofluoroacetate was added dropwise to a suspension of 22.4 mL of chlorotriethylsilane, 8.0 g of zinc, and 250 mL of acetonitrile, over 2 hours at −20° C. The mixture was further stirred for 1.5 hours at −20° C. 2-cyclopenten-1-one in an amount of 5.0 g was added dropwise to the reaction solution, and the mixture was stirred for 15 hours at −20° C. The reaction was quenched with 1M hydrochloric acid, followed by concentration under reduced pressure. After extraction of the residue with diethyl ether twice, the organic layers were combined. The combined organic layer was washed with a saturated aqueous solution of sodium chloride, and was subsequently dried over anhydrous sodium sulfate. After the desiccant was filtered off, the filtrate was concentrated under reduced pressure. The residue was purified by column chromatography (silica gel: Wako gel C200 (produced by Wako Pure Chemical Industries Ltd.), eluent: hexane-ethyl acetate=10:1 to 8:1), thereby yielding 6.2 g of (2SR)ethyl 2-bromo-2-fluoro-2-[(1RS)-3-oxocyclopentyl]acetate and 4.4 g of (2RS)ethyl 2-bromo-2-fluoro-2-[(1RS)-3-oxocyclopentyl]acetate.

1. stirringthe mixture was stirred for 15 hours at −20° C
2. customThe reaction was quenched with 1M hydrochloric acid
3. concentrationfollowed by concentration under reduced pressure
4. extractionAfter extraction of the residue with diethyl ether twice
5. washThe combined organic layer was washed with a saturated aqueous solution of sodium chloride
6. dry with materialwas subsequently dried over anhydrous sodium sulfate
7. filtrationAfter the desiccant was filtered off
8. concentrationthe filtrate was concentrated under reduced pressure
9. customThe residue was purified by column chromatography (silica gel: Wako gel C200 (produced by Wako Pure Chemical Industries Ltd.), eluent: hexane-ethyl acetate=10:1 to 8:1)