sodium hydroxide T=200°C; P=0.1 Torr;

1: 100 percent / Et3N / CH2Cl2 / 2 h / Ambient temperature 2: 97 percent / NaI / acetone / 16 h / Heating 3: 50 percent / t-BuLi, HMPA / tetrahydrofuran / -78 °C 4: 98 percent / CH3SO3H / CH2Cl2 / Ambient temperature 5: 89 percent / NaBH4 / methanol / 2.5 h 6: 83 percent / p-TsOH / benzene / 1 h / Heating 7: 87 percent / DDQ / benzene / 4 h / Heating View Scheme