反应详情

温度

-78 °C

(4R)-4-Benzyl-3-[5-(4-methoxyphenyl)pentanoyl]-1,3-oxazolidin-2-one (Reference Example 19) (1.4 g) was dissolved in dichloromethane (25 ml), and dibutylborane triflate (1M, 8.3 ml) and diisopropylethylamine (1.6 ml) were added thereto under ice-cooling. After 30 minutes, the reaction mixture was cooled to −78° C. and added dropwise to a solution of N-bromosuccinimide (NBS) (1.1 g) in dichloromethane (25 ml) which had been cooled to −78° C., via a cannula. After 2 hours, an aqueous sodium sulfite solution was added thereto and the resulting mixture was stirred at room temperature for 30 minutes. Chloroform was added to the reaction mixture to effect separation and extraction. The organic layer was dried, concentrated, and then the residue was purified by a silica gel chromatography (150 g, ethyl acetate:hexane=1:4) to obtain (4R)-4-benzyl-3-[(2R)-2-bromo-5-(4-methoxyphenyl)pentanoyl]-1,3-oxazolidin-2-one (0.9 g).

1. temperatureunder ice-cooling
2. temperaturehad been cooled to −78° C., via a cannula
3. waitAfter 2 hours
4. customseparation and extraction
5. customThe organic layer was dried
6. concentrationconcentrated
7. customthe residue was purified by a silica gel chromatography (150 g, ethyl acetate:hexane=1:4)