Acetic Acid → (3S)-3-(2-Hydroxyethyl)-4-methyl-5-oxo-1-[(1R)-1-phenylethyl]pyrrolidine-3-carboxylic acid tert-butyl ester

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Reaction Steps

The aforementioned crude (3S)-3-[2-(tert-butyldimethylsilyloxy)ethyl]-4-methyl-5-oxo-1-[(1R)-1-phenylethyl]pyrrolidine-3-carboxylic acid tert-butyl ester was dissolved in tetrahydrofuran (10 mL). Then, acetic acid (0.572 mL, 10.0 mmol) and a 1 M solution of tetrabutylammonium fluoride in tetrahydrofuran (10.0 mL, 10.0 mmol) were sequentially added in a nitrogen atmosphere. After stirring at room temperature for 12 hours, the reaction solution was poured into a mixture of ethyl acetate (100 mL) and brine (50 mL), followed by extraction with ethyl acetate (200 mL). The organic layer was washed with brine (50 mL), and then dried over anhydrous sodium sulfate and filtered. The filtrate was then concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (hexane:ethyl acetate=1:1→1:2) to give 1.56 g (90%, two steps) of the diastereomer mixture title compound as a colorless oil.

Provenance & Evidence