反应详情

温度

-78 °C

(4R,5S)-4-Methyl-5-phenyl-oxazolidin-2-one (25.21 g, 142.269 mmol) is dissolved in anhydrous THF (100 mL) and cooled to −78° C. n-Butyl lithium (2.5 M in hexanes, 62.60 mL, 156.5 mmol) is added dropwise over 10 min. The reaction is stirred at −78° C. for 10 min. Phenylacetyl chloride (20.73 mL, 156.5 mmol) is dissolved in anhydrous THF (50 mL) and added dropwise over 10 min. The reaction is stirred at −78° C. for 2 h. The reaction is poured onto brine (300 mL) and extracted with ethyl acetate (2×250 mL). Extracts are combined, dried over anhydrous sodium sulfate, filtered, and concentrated to a yellow oil which solidified upon standing. Therude product is purified by column chromatography over silica eluting with 5→45% ethyl acetate in hexanes to afford (4R,5S)-4-methyl-5-phenyl-3-phenylacetyl-oxazolidin-2-one as a white solid: 1H NMR (400 MHz, DMSO-D6) δ 0.8 (d, J=6.6 Hz, 3 H) 4.2 (m, 2 H) 4.8 (m, 1 H) 5.9 (d, J=7.3 Hz, 1 H) 7.2 (m, 3 H) 7.3 (m, 5 H) 7.4 (m, 2 H); LC/MS 296.2 (M+1), 294.1 (M−1).

1. additionis added dropwise over 10 min
2. additionadded dropwise over 10 min
3. stirringThe reaction is stirred at −78° C. for 2 h
4. additionThe reaction is poured onto brine (300 mL)
5. extractionextracted with ethyl acetate (2×250 mL)
6. dry with materialdried over anhydrous sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated to a yellow oil which
9. customTherude product is purified by column chromatography over silica eluting with 5→45% ethyl acetate in hexanes