Ozone → (3S)-5-Oxo-3-(2-oxoethyl)-1-[(1R)-1-phenylethyl]pyrrolidine-3-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of (3S)-3-allyl-5-oxo-1-[(1R)-1-phenylethyl]pyrrolidine-3-carboxylic acid tert-butyl ester (3.29 g, 10.0 mmol) in methanol (100 mL) was bubbled with ozone at −74° C. When the reaction solution turned blue, ozone bubbling was stopped and then the solution was bubbled with nitrogen at the same temperature. Sodium borohydride (568 mg) was added at the same temperature, and the mixture was stirred for 1.5 hours while heating to −40° C. The reaction solution was poured into a 10% citric acid solution (50 mL), and then the mixture was stirred sufficiently. The methanol component was evaporated, and then the aqueous layer was extracted with ethyl acetate (200 mL, 100 mL). The organic layer was washed with brine (50 mL×2), and then dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated under reduced pressure into a slurry. Hexane was added to the resulting residue, and the slurry was stirred. The solid was collected by filtration and dried to give 1.70 g of the title compound as a white solid. The filtrate was concentrated, hexane was added to the resulting residue, and the slurry was stirred. The solid was collected by filtration to give 0.66 g of the title compound as a white solid. The same operation was repeated to give 0.35 g of the title compound as a white solid (total yield: 2.71 g, 82%).

Provenance & Evidence