Isobutyl chloroformate → tert-butyl (2S)-2-(2-hydroxyethyl)pyrrolidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

Diisopropylethylamine (575 μl) was added to a solution of 2-[(2S)-1-tert-butoxycarbonylpyrrolidin-2-yl]acetic acid (688 mg) in tetrahydrofuran (15 ml, and the mixture was cooled to −20° C. Isobutyl chloroformate (428 μl) was added thereto, and the mixture was stirred at −20° C. for 45 minutes. The resulting solid was filtered off, and the solid was washed with tetrahydrofuran. Sodium borohydride (227 mg) was added to the filtrate, and the mixture was stirred at room temperature for 5 minutes. Then, methanol (5 ml) was added thereto, and the mixture was stirred at room temperature for 5 minutes. Ethyl acetate and water were added to the reaction solution to separate the aqueous and organic layers. The aqueous layer was subjected to extraction with ethyl acetate. The organic layers were combined, dried over anhydrous sodium sulfate and then concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography (n-hexane-ethyl acetate) to obtain tert-butyl (2S)-2-(2-hydroxyethyl)pyrrolidine-1-carboxylate (606 mg).

Provenance & Evidence