1: triphenylphosphine; diisopropyl azodicarboxylate / benzene / 1.5 h / 23 °C 2: 326 mg / LiOH; Et3N / methanol; H2O / 2 h / 23 °C 3: 66 percent / Et3N / acetonitrile / 7 h / 23 °C View Scheme

1: With di-isopropyl azodicarboxylate; triphenylphosphine; 4-nitro-benzoic acid in benzene T=23°C; Mitsunobu reaction; 1.5 h; 2: With lithium hydroxide; triethylamine in methanol; water T=20°C; 2 h;