Acetic Acid → (2R,4S)-2-[(4S,5S)-3-Acetyl-4-(3,5-difluoro-benzyl)-2,2-dimethyl-oxazolidin-5-yl]-4-hydroxy-pyrrolidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

Add dropwise diisopropyl azodicarboxylate (0.20 mL, 1.04 mmol) to a solution of (2R,4R)-2-[(4S,5S)-3-acetyl-4-(3,5-difluorobenzyl)-2,2-dimethyloxazolidin-5-yl]-4-hydroxypyrrolidine-1-carboxylic acid tert-butyl ester (0.314 g, 0.69 mmol), acetic acid (0.06 mL, 1.04 mmol) and 4-diphenylphosphanyl-benzoic acid 2-trimethylsilanyl-ethyl ester (0.42 g, 1.04 mmol, prepared according to Synlett 2003 (4) p 473-476) in tetrahydrofuran (3 mL). Stir solution 18 hours, then add a 1M solution of tetrabutylammonium fluoride in tetrahydrofuran (3 mL) and stir 90 minutes. Add a 1N aqueous solution of sodium hydroxide (3 mL) and stir 30 minutes. Dilute with ethyl acetate and water. Evaporate the organic layer and dissolve in methanol (30 mL). Add sodium carbonate (0.365 g) and water (1 mL) and stir 18 hours. Evaporate and partition with ethyl acetate and water, wash organic layer with saturated sodium chloride solution, dry with magnesium sulfate and purify on silica gel with hexane/ethyl acetate mixtures to give the title compound as a foam (0.295 g, 95%).

Provenance & Evidence