反应详情

To a solution of cis-(3-hydroxy-cyclobutyl)-acetic acid methyl ester (570 mg, 3.96 mmol), triphenylphosphine (2.08 g, 7.92 mmol), and 4-nitrobenzoic acid (1.32 g, 7.92 mmol) in dry THF (50 mL), 40% diethyl azodicarboxylate in toluene (1.42 mL, 7.92 mmol) is added at room temperature. The mixture is stirred at room temperature for 15 hours. The solvent is removed under reduced pressure, and the obtained residue is purified by silica gel column chromatography to give trans-4-nitro-benzoic acid 3-methoxycarbonylmethyl-cyclobutyl ester (558 mg, 48%); TLC (hexane/AcOEt, 3:1) Rf 0.31, 1H NMR (400 MHz, chloroform-d) δ ppm 2.28-2.35 (m, 2H), 2.44-2.51 (m, 2H), 2.56 (d, 2H), 2.82-2.87 (m, 1H), 3.69 (s, 3H), 5.33-5.40 (m, 1H) 8.18-8.30 (m, 4H).

1. customThe solvent is removed under reduced pressure
2. customthe obtained residue is purified by silica gel column chromatography