1: 81 percent / sodium hydride / tetrahydrofuran / 1 h / Ambient temperature 2: 92 percent / 65percent aq. acetic acid / tetrahydrofuran / 1.5 h / 40 °C 3: diisobutylaluminum 2,6-di-tert-butyl-4-methylphenoxide / toluene / 1.) -78 deg C, 15 min; 2.) -20 deg C, 2 h 4: Et3N / p-toluenesulfonic acid / CH2Cl2 / 0.17 h / Ambient temperature 5: K2CO3 / methanol / 1 h / 45 °C 6: triphenylphosphine, diethyl azodicarboxylate / benzene / 2 h / Ambient temperature 7: p-toluenesulfonic acid, Et3N / methanol / 1 h / Ambient temperature 8: NaN3, dimethylsulfoxide / 19 h / 45 °C 9: toluene / 20 h / 70 °C View Scheme