tert-Butanol → tert-Butyl {(3S)-3-methyl-5-oxo-1-[(1R)-1-phenylethyl]pyrrolidin-3-yl}carbamate

Participants

Reaction Steps

With cooling with ice, trifluoroacetic acid (7 ml) was added to a dichloromethane (14 ml) solution of tert-butyl (3S)-3-methyl-5-oxo-1-[(1R)-1-phenylethyl]pyrrolidine-3-carboxylate (I-342) (800 mg, 2.64 mmol), followed by stirring at room temperature for 13 hours. The reaction liquid was concentrated under reduced pressure, dissolved in chloroform, washed with saturated brine (60 ml). After drying over anhydrous sodium sulfate and concentration under reduced pressure, the resulting residue was dissolved in toluene (20 ml), then triethylamine (735 μl, 5.27 mmol) and diphenylphosphorylazide (739 μl, 3.43 mmol) were added, followed by stirring at room temperature for 30 minutes, then by stirring in an oil bath at 125° C. for 3 hours. tert-Butanol (20 ml) was added to the reaction liquid, followed by stirring in an oil bath at 100° C. for 11 hours. The reaction liquid was concentrated under reduced pressure, the residue was dissolved in ethyl acetate, washed with saturated brine. After drying over anhydrous sodium sulfate and concentration, the resulting residue was purified by silica gel column chromatography (eluent, n-hexane:ethyl acetate=2:1→1:4, v/v) to obtain the entitled compound (500 mg, 60%) as a colorless oily substance.

Provenance & Evidence