Citric Acid → HCID 67490916, compound

Participants

Reaction Conditions

Reaction Steps

A 1.8 M solution of lithium diisopropylamide in tetrahydrofuran (3.10 mL) was added dropwise to a solution of (3S)-3-[2-(tert-butyldimethylsilyloxy)ethyl]-5-oxo-1-[(1R)-1-phenylethyl]pyrrolidine-3-carboxylic acid tert-butyl ester (2.24 g, 5.00 mmol) in tetrahydrofuran (20 mL) in a nitrogen atmosphere at −72° C. over five minutes. After stirring at the same temperature for 10 minutes, methyl iodide (0.34 mL, 5.50 mmol) was added. The mixture was stirred at the same temperature for 15 minutes and then heated to −10° C. over 10 minutes. Thereafter, a 10% citric acid aqueous solution (5 mL) was added. The reaction solution was poured into a mixture of ethyl acetate (100 mL) and 10% citric acid solution (50 mL), followed by extraction with ethyl acetate (200 mL). The organic layer was washed with brine (50 mL×2), dried over anhydrous sodium sulfate, and filtered. The filtrate was then concentrated under reduced pressure. The resulting dark brown residue was used for the next reaction without further purification.

Provenance & Evidence