反应详情

温度

-55 °C

A solution of (4S)-4-isopropyl-1,3-oxazolidin-2-one (26 g, 0.2 mol) in anhydrous tetrahydrofuran (600 ml) was cooled to −78° C. under a nitrogen atmosphere and treated with n-butyl lithium, 2.5M in hexanes (80 ml, 0.2 mol) keeping the temperature below −65° C. Once the addition was complete the reaction mixture was allowed to warm to −55° C. and stirred at this temperature for 30 minutes. The mixture was cooled back down to −78° C. and treated dropwise with a solution of 4-pentenoyl chloride (23.7 g, 0.2 mol) in anhydrous tetrahydrofuran (100 ml). After stirring at −78° C. for 30 minutes the reaction mixture was allowed to warm to room temperature. Saturated aqueous ammonium chloride solution (1 L) was added and the mixture was extracted with ethyl acetate (2×). The combined organic extracts were dried over anhydrous magnesium sulphate, filtered and the solvent removed under reduced pressure. The oil was purified by column chromatography on silica gel eluting with a solvent gradient of 100:0 (pentane:ethyl acetate) gradually changing to 70:30 (pentane:ethyl acetate) to afford the title compound as a yellow oil (36.3 g).

1. customthe temperature below −65° C
2. additionOnce the addition
3. temperatureThe mixture was cooled back down to −78° C.
4. stirringAfter stirring at −78° C. for 30 minutes the reaction mixture
5. temperatureto warm to room temperature
6. extractionthe mixture was extracted with ethyl acetate (2×)
7. dry with materialThe combined organic extracts were dried over anhydrous magnesium sulphate
8. filtrationfiltered
9. customthe solvent removed under reduced pressure
10. customThe oil was purified by column chromatography on silica gel eluting with a solvent gradient of 100:0 (pentane:ethyl acetate)