Citric Acid → HCID 57237021, compound

Participants

Reaction Steps

To a solution of (2R,4S)-N-allyloxycarbonyl-2-(2-allyloxycarbonylamino-2-methoxycarbonylethyl)-4-(triphenylmethylthio)pyrrolidine prepared in REFERENCE EXAMPLE 2-2 (810 mg, 1.32 mmol) in tetrahydrofuran (5 ml) was added lithium chloride (100 mg, 2.58 mmol), sodium borohydride (110 mg, 2.59 mmol) and ethanol (5 ml) under a nitrogen atmosphere, and the mixture was stirred overnight at room temperature. The reaction mixture was acidified with 10% aqueous citric acid under ice-cooling, and then the organic solvent was removed in vacuo. The residual aqueous solution was extracted with methylene chloride (1×40 ml, 2×20 ml), and the combined organic layer was washed successively with water and saturated aqueous sodium chloride. After drying over anhydrous sodium sulfate, the solvent was removed in vacuo, and the residue was subjected to silica gel column chromatography (heptane-ethyl acetate) to give (2R,4S)-N-allyloxycarbonyl-2-(2-allyloxycarbonylamino-3-hydroxypropyl)-4-(triphenylmethylthio)pyrrolidine (440 mg, yield: 57%).

Provenance & Evidence