反应详情

温度

-78 °C

To a cooled solution of (S)-2,2-dimethyl-4-(2-oxo-ethyl)-oxazolidine-3-carboxylic acid t-butyl ester (2.05 g, 8.43 mmol) in dry tetrahydrofuran (25 mL) was added 1.4M methyl magnesium bromide in diethyl ether (6.02 mL) at −78° C. The mixture was stirred at −78° C. for 30 min and then warmed to −5° C. The mixture was extracted with diethyl ether and ammonium chloride solution. The organic layer was dried and concentrated. The crude mixture was purified by ISCO flash chromatography (0 to 60% ethyl acetate/hexanes) to give two fractions. The first fraction afforded (S)-4-((S)-2-hydroxy-propyl)-2,2-dimethyl-oxazolidine-3-carboxylic acid t-butyl ester as a colorless oil (870 mg): 1H NMR (300 MHz, CDCl3) δ ppm 1.20 (d, J=6.0 Hz, 3H), 1.42-1.60 (m, 1H), 1.50 (s, 12H), 1.55 (s, 3H), 1.68-1.88 (m, 1H), 3.66 (d, J=8.8 Hz, 1H), 3.69-3.80 (m, 1H), 3.94-4.08 (m, 1H), 4.17-4.30 (m, 1H), 4.62 (br. s., 1H); The second fraction afforded (S)-4-((R)-2-hydroxy-propyl)-2,2-dimethyl-oxazolidine-3-carboxylic acid t-butyl ester as a white solid (740 mg): 1H NMR (300 MHz, CDCl3) δ ppm 1.22 (d, J=6.0 Hz, 3H), 1.49 (s, 12H), 1.58 (br. s., 3H), 1.75-1.90 (m, 2H), 2.56 (br. s., 1H), 3.75-3.93 (m, 2H), 3.95-4.05 (m, 1H), 4.03-4.20 (m, 1H).

1. temperaturewarmed to −5° C
2. extractionThe mixture was extracted with diethyl ether and ammonium chloride solution
3. customThe organic layer was dried
4. concentrationconcentrated
5. customThe crude mixture was purified by ISCO flash chromatography (0 to 60% ethyl acetate/hexanes)
6. customto give two fractions