1: Ph3P, diethylazadicarboxylate / CH2Cl2 / 5 h / Ambient temperature 2: pyridine / Ambient temperature 3: 61 percent / 80percent AcOH / 6 h / Ambient temperature 4: 1.) t-BuOK, 2.) MeONa / 1.) DMSO, RT, 1 h, 2.) DMF View Scheme