反应详情

Deoxo-flour (4.5 mL, 24.16 mmoles) was added drop-wise to a solution of (R)-benzyl 2-((S)-3-hydroxy-1-methoxy-1-oxopropan-2-ylcarbamoyl)pyrrolidine-1-carboxylate (8.5 g, 22.0 mmoles) in CH2Cl2 (150 mL) at −20° C. The solution was stirred for 30 min and BrCCl3 (7.8 mL, 79.0 mmoles) was added drop-wise followed by DBU (11.8 mL, 79 mmoles). The reaction was stirred at 2-3° C., for 10 h., quenched with Satd. Aq. NaHCO3 solution and extracted with ethyl actetate. The organic layer was concentrated and chromatographed on silica gel (10% ethyl acetate/90% chloroform) to yield 6.95 of (R)-methyl 2-(1-(benzyloxycarbonyl)pyrrolidin-2-yl)oxazole-4-carboxylate.

1. stirringThe reaction was stirred at 2-3° C., for 10 h.
2. customquenched with Satd
3. extractionAq. NaHCO3 solution and extracted with ethyl actetate
4. concentrationThe organic layer was concentrated
5. customchromatographed on silica gel (10% ethyl acetate/90% chloroform)