3-Boc-2,2-dimethyloxazolidine-4-carboxaldehyde, (S)-(-)- → (R)-4-[(1R,2S)-3-(3,5-difluorophenyl)-1-hydroxy-2-nitropropyl]-2,2-dimethyloxazolidine-3-carboxylic acid tert-butyl ester

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Reaction Steps

Add tetrabutylammonium fluoride in 5 minutes (50 mL, 50 mmol, 1.0 M solution in tetrahydrofuran) to a solution of (S)-4-formyl-2,2-dimethyloxazolidine-3-carboxylic acid tert-butyl ester (200 g, 873.362 mmol) and 1,3-difluoro-5-(2-nitroethyl)-benzene (164 g, 877.005 mmol) in tetrahydrofuran (1.2 L) at 8° C. Allow to warm to room temperature and stir for 14 hours. Partition between ethyl acetate (4 L) and saturated aqueous sodium chloride (1.5 L). Wash the organic layer with saturated aqueous ammonium chloride, saturated aqueous sodium chloride, water, dry (magnesium sulfate), filter and concentrate to give 379 g of a crude waxy pale orange solid. Recrystallize in dichloromethane/hexanes to give the title compound (137.15 g, 37.7%).

Provenance & Evidence