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

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Reaction Steps

Dissolve acetic acid 3-(2-nitroethyl)-phenyl ester (25.53 g, 121.6 mmol) and tert-butyl (R)-(+)-4-formyl-2,2-dimethyl-3-oxazolidinecarboxylate (Gardner's aldehyde) (22.38 g, 97.61 mmol) in dry tetrahydrofuran (200 mL). Cool in ice bath and add tetrabutylammonium fluoride (98 mL, 98 mmol, 1.0 M in tetrahydrofuran) and stir for 15 minutes. Pour into ice water (2.7 L), wash with 1 N hydrochloric acid (200 mL), saturated aqueous sodium chloride, dry (magnesium sulfate), filter through a pad of silica gel and concentrate. Purify using silica gel chromatography, eluting with 5:95 ethyl acetate:dichloromethane, followed by 2 separate crystallizations using hexanes/dichloromethane to give the desired compound (18.372 g, 43% total yield).

Provenance & Evidence