反应详情

温度

-45 °C

Under a nitrogen atmosphere, to a solution (500 mL) of ethyl (3R)-3-hydroxy-3,6-dihydro-2H-pyran-4-carboxylate (23.5 g) in tetrahydrofuran was added dropwise N,N-diisopropylethylamine (35.7 mL) at −70° C. Then, methanesulfonyl chloride (13.7 mL) was added dropwise, and the mixture was stirred at −45° C. for 2 hr. The mixture was again cooled to −70° C., N,N-diisopropylethylamine (14.6 mL) and thioacetic acid (35.7 mL) were respectively added, and the mixture was stirred at −45° C. for 2 hr. The reaction mixture was treated with 1N hydrochloric acid (300 mL) and extracted with diisopropyl ether (300 mL×2). The extract was washed with saturated aqueous sodium hydrogen carbonate solution (300 mL) and water (300 mL), dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was subjected to silica gel column chromatography (hexane/ethyl acetate=6:1→4:1) to give the title compound (19.5 g, 62%).

1. temperatureThe mixture was again cooled to −70° C.
2. stirringthe mixture was stirred at −45° C. for 2 hr
3. extractionextracted with diisopropyl ether (300 mL×2)
4. washThe extract was washed with saturated aqueous sodium hydrogen carbonate solution (300 mL) and water (300 mL)
5. dry with materialdried over anhydrous magnesium sulfate
6. concentrationconcentrated under reduced pressure