反应详情

23.5 g of ethyl (3R)-4,4,4-trifluorovalinate (diastereomer mixture, crude product about 70%) and 18.1 ml (130 mmol) of triethylamine were dissolved in 235 ml of THF, and 32.3 g (130 mmol) of N-(benzyloxycarbonyloxy)succinimide were added. The reaction mixture was stirred at RT overnight and then diluted with ethyl acetate. The mixture was washed successively with sat. sodium bicarbonate solution, 1 N hydrochloric acid and sat. sodium chloride solution. The organic phase was dried over magnesium sulphate and concentrated under reduced pressure. The crude product was purified by chromatography on silica gel (mobile phase cyclohexane/ethyl acetate 6:1). This gave 22.1 g of the target product (about 80% of theory, diastereomer ratio about 2:1).

1. washThe mixture was washed successively with sat. sodium bicarbonate solution, 1 N hydrochloric acid and sat. sodium chloride solution
2. dry with materialThe organic phase was dried over magnesium sulphate
3. concentrationconcentrated under reduced pressure
4. customThe crude product was purified by chromatography on silica gel (mobile phase cyclohexane/ethyl acetate 6:1)