反应详情

To a stirred mixture of (±)-trans-4-benzyloxycarbonylamino-3-hydroxy-piperidine-1-carboxylic acid tert-butyl ester (1 mmol, 0.35 g), triphenylphosphine (1.5 mmol , 0.393 g) and p-nitrobenzoic acid (1.5 mmol, 0.25 g) in anhydrous THF (6 mL) at −60° C. was added DIAD drop-wise over 5 min period. After completion of addition, the reaction mixture was stirred for 4 h during which period the reaction mixture was slowly let attain room temperature. The reaction mixture was diluted with ether (100 mL) and washed with saturated sodium bicarbonate solution (2×50 mL). The organic layer was dried, filtered and concentrated under reduced pressure. The residue was purified by flash silica gel column chromatography by eluting with 30% ethyl acetate in hexanes to get (±)-cis-4-benzyloxycarbonylamino-3-(4-nitro-benzoyloxy)-piperidine-1-carboxylic acid tert-butyl ester.

1. additionAfter completion of addition
2. customwas slowly let attain room temperature
3. washwashed with saturated sodium bicarbonate solution (2×50 mL)
4. customThe organic layer was dried
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. customThe residue was purified by flash silica gel column chromatography
8. washby eluting with 30% ethyl acetate in hexanes