Benzyl chloroformate → Benzyloxycarbonyl-L-proline

Participants

Reaction Steps

To a solution of (S)-proline (25 g:0.22 mole) and sodium hydroxide (8.7 g:0.22 mole) in 150 ml of water was slowly added a solution of benzylchloroformate (43.5 g:0.26 mole) and sodium hydroxide (11.6 g:0.29 mole) in 75 ml of water with stirring under cooling on ice over 30 minutes, followed by continuing the stirring at the same temperature for 15 minutes. From the reaction mixture, excess benzylchloroformate was removed by extraction with 150 ml of chloroform. The aqueous layer was acidified with 5N hydrochloric acid, and the resulting oily product was extracted with chloroform. After drying the chloroform layer over magnesium sulfate, chloroform was removed by evaporation to give 52.2 g of (S)-1-carbobenzoxypyrrolidine-2-carboxylic acid as oil. Yield: 96%.

Provenance & Evidence