1: 1) NaOMe, 2) PPh3Br2 / 1) MeOH, 40 deg C, 4 h, 2) CH2Cl2, 0 deg C, 1 h 2: 86 percent / acetonitrile / 24 h / Heating 3: 1) Natriumsilazid (NaHMDS) / 1) Et2O, a) -78 deg C, 4 h, b) -40 - -30 deg C, 0.5 h, 2) Et2O, -78 deg C to r.t., 12 h 5: 80 percent / Py / tetrahydrofuran / 1) -20 deg C, 0.5 h, 2) r.t., 3 h View Scheme