Chloroacetic Acid → (3S,4R)-tert-butyl 3-(4-bromo-2-nitrophenylamino)-4-(2-chloroacetoxy)pyrrolidine-1-carboxylate

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Reaction Steps

To a mixture of (3S,4S)-tert-butyl 3-(4-bromo-2-nitrophenylamino)-4-hydroxypyrrolidine-1-carboxylate (2.50 mmol, 1.0 g), chloroacetic acid (3.0 mmol, 300 mg) and triphenylphosphine (3.0 mmol, 850 mg) in tetrahydrofuran (40 mL) add diethylazodicarboxylate (3.0 mmol, 600 mg) and stir at room temperature for 12 h. Remove the solvent, add ethyl acetate (50 mL) to the residue and wash with water and brine. Dry over anhydrous sodium sulfate and evaporate. Purify the residue by column chromatography, eluting with 20% ethyl acetate in methylene chloride to obtain the title compound as a yellow solid (1.10 g, 98%). 1H NMR (500 MHz, CDCl3) δ 8.35 (s, 1H), 8.20 (m, 1H), 7.60 (m, 1H), 6.82 (m, 1H), 5.55 (d, J=6.8 Hz, 1H), 4.32 (m, 1H), 4.13 (bd, J=8.2 Hz, 2H), 3.90 (m, 1H), 3.79 (m, 1H), 3.74 (dd, J=4.2, 10.4 Hz, 1H), 3.25 (t, J=7.20 Hz, 1H), 1.41 (s, 9H).

Provenance & Evidence