4-Nitrobenzoic Acid → cis-2-(Tert-butoxycarbonyl)amino-1-(4-nitrobenzoyloxy)cyclopentane

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Reaction Steps

To a solution of trans-2-(tert-butoxycarbonyl)aminocyclopentan-1-ol (Prepn. 47, 3.00 g) triphenyl phosphine (5.90 g) and 4-nitrobenzoic acid (2.50 g) in THF (90 mL) was added, at 0° C., diisopropyl azodicarboxylate (4.50 mL). After stirring for 4 h, the solvent was evaporated and the crude product was purified by flash chromatography (SiO2, CH2Cl2:acetone 99:1) to give cis-2-(tert-butoxycarbonyl)amino-1-(4-nitrobenzoyloxy)cyclopentane (3.70 g, 70%). 1H-NMR (300 MHz, DMSO-d6, ppm from TMS): δ 8.33 (2H, d), 8.23 (2H, d), 7.08 (1H, d), 5.25 (1H, m), 3.92 (1H, m), 1.40-2.10 (6H, m), 1.28 (9H, s).

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