Water → 1-Chloro-2-(2,4-difluorophenyl)-3-pivaloyloxybutan-2-ol

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Reaction Conditions

Reaction Steps

First, 8.9 mL (8.0 mmol) of a 0.9 M solution of 2,4-difluorophenylmagnesium bromide prepared by the same method as that in Example 3 was cooled to 0° C., and a solution of 0.83 g (4.0 mmol) of (R)-1-chloro-3-pivaloyloxybutan-2-one in 10 mL of toluene was added dropwise thereto over a period of 5 minutes. After the completion of the dropwise addition, stirring was continued for another 1 hour, and 20 mL of a saturated aqueous solution of ammonium chloride was added to stop the reaction. Furthermore, 10 mL of water was added, and extraction was performed with ethyl acetate (30 mL×2). After drying over anhydrous sodium sulfate, concentration was performed under reduced pressure to obtain 1.57 g of a crude product. A quantitative analysis was performed by HPLC. Thereby, the title compound was obtained in a yield of 94% ((2S,3R)/(2R,3R)=93/7 (the diastereomeric ratio was measured by HPLC under the same HPLC measurement conditions as those in Example 19)).

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