1: 90 percent / Ac2O / 0.75 h / 140 °C 2: 78 percent / aq. NaOH / methanol / 2 h / Heating 3: diethyl ether 4: 86 percent / phosphorous tribromide / 1.) 25 deg C, 12 h, 2.) 80 deg C, 1 h 5: NaI / dimethylformamide / 3 h / 50 °C 6: 1,8-diazabicyclo<5.4.0>undec-7-ene (DBU) / dimethylformamide / 3 h / 80 °C View Scheme

1: 90 percent / Ac2O / 0.75 h / 140 °C 2: 78 percent / aq. NaOH / methanol / 2 h / Heating View Scheme