反应详情

To a mixture of (4R,5S)-(+)-4-methyl-5-phenyl-2-oxazolidinone (3.22 g) and tetrahydrofuran (35 ml) at -70° C., under nitrogen was added 1.625M n-butyllithium (12.31 mL) and the mixture was stirred for 15 min. 2-Methyl-4,4,4-trifluorobutyryl chloride (3.5 g) was added to the reaction mixture which was stirred for 15 min at -70° C. and then at 0° C. for 1 hour. The reaction was quenched with ammonium chloride and extracted with ethyl acetate. The organic phase was washed (saturated NaHCO3, brine) and dried (MgSO4). Evaporation and flash chromatography, eluting with 5:95 then 1:9 ethyl acetate:petroelum ether, afforded the two diastereomeric products. Recrystallization from hexane at 20° C. gave (4R,5S)-4-methyl-3-((2R)-2-methyl-4,4,4-trifluorobutyryl)-5-phenyl-2-oxazolidinone (2.376 g, 42%) as colorless needles; mp 72.5°-73.5° C.; TLC, Rf =0.43, 1:9 ethyl acetate:petroleum ether; MS(CI): 316 (M+H).

1. stirringwas stirred for 15 min at -70° C.
2. waitat 0° C. for 1 hour
3. customThe reaction was quenched with ammonium chloride
4. extractionextracted with ethyl acetate
5. washThe organic phase was washed (saturated NaHCO3, brine)
6. dry with materialdried (MgSO4)
7. customEvaporation and flash chromatography
8. washeluting with 5:95
9. custom1:9 ethyl acetate:petroelum ether, afforded the two diastereomeric products
10. customRecrystallization from hexane at 20° C.