1: aq. KOH / ethane-1,2-diol / 8 h / Heating 2: 53 percent / polyphosphoric acid / 2 h / 100 - 105 °C 3: 48percent aq. HBr, CH3CO2H / 2 h / Heating 4: NaBH4 / ethanol / 0.5 h 5: p-toluenesulfonic acid / benzene / 1 h / Heating 6: pyridine / 3 h 7: 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / dioxane / 1 h / Heating 8: K2CO3 / methanol; tetrahydrofuran / 0.5 h / 0 °C View Scheme

Multi-step reaction with 3 steps 1: aq. KOH / ethane-1,2-diol / 8 h / Heating2: 53 percent / polyphosphoric acid / 2 h / 100 - 105 °C3: 48percent aq. HBr, CH3CO2H / 2 h / Heating  

Multi-step reaction with 6 steps 1: aq. KOH / ethane-1,2-diol / 8 h / Heating2: 53 percent / polyphosphoric acid / 2 h / 100 - 105 °C3: 48percent aq. HBr, CH3CO2H / 2 h / Heating4: NaBH4 / ethanol / 0.5 h5: p-toluenesulfonic acid / benzene / 1 h / Heating6: pyridine / 3 h  

Multi-step reaction with 4 steps 1: aq. KOH / ethane-1,2-diol / 8 h / Heating2: 53 percent / polyphosphoric acid / 2 h / 100 - 105 °C3: 48percent aq. HBr, CH3CO2H / 2 h / Heating4: NaBH4 / ethanol / 0.5 h  

Multi-step reaction with 2 steps 1: aq. KOH / ethane-1,2-diol / 8 h / Heating2: 53 percent / polyphosphoric acid / 2 h / 100 - 105 °C  

Multi-step reaction with 2 steps 1: 98.6 percent / Et3N / CH2Cl2 / 0.25 h / 0 - 5 °C2: aq. tricaprylylmethylammonium chloride / benzene / 15 h / Heating