反应详情

温度

0 °C

To a suspension of (2S,4R)-2-carboxy-4-hydroxypyrrolidine (300 g) in a mixture of tetrahydrofuran (1.5 l) and water (1.5 l) was added dropwise a solution of allyl chloroformate (292 ml) in tetrahydrofuran (300 ml) at 0° C. while adjusting pH to around 9 with 4N aqueous sodium hydroxide. After stirring at 0° C. for 1 hour at pH 9, the aqueous layer was saturated with sodium chloride, and the mixture was diluted with ethyl acetate (1 l). The aqueous layer was separated, washed with ethyl acetate (1 l). After adjusting pH to around 2 with 12N hydrochloric acid, the emulsion was extracted with two portions of ethyl acetate (1 l×2). The combined extract was dried over magnesium sulfate and evaporated in vacuo to give (2S,4R)-1-allyloxycarbonyl-2-carboxy-4-hydroxypyrrolidine (426.2 g}.

1. customThe aqueous layer was separated
2. washwashed with ethyl acetate (1 l)
3. extractionthe emulsion was extracted with two portions of ethyl acetate (1 l×2)
4. extractionThe combined extract
5. dry with materialwas dried over magnesium sulfate
6. customevaporated in vacuo