1: 49 percent / titanium(IV) chloride / CH2Cl2 / 1 h / -10 °C 2: 96 percent / sodium chlorite, resorcinol / dioxane / 24 h / pH 4.4 3: 78 percent / boron trichloride / CH2Cl2 / 0.5 h / -10 °C View Scheme

Multi-step reaction with 3 steps 1: 73 percent / copper bronze powder / 24 h / 200 - 210 °C2: 40 percent / hydrobromic acid, hydroiodic acid / 144 h / Heating3: 61 percent / potassium carbonate / acetone / 6 h  

Multi-step reaction with 2 steps 1: 40 percent / hydrobromic acid, hydroiodic acid / 144 h / Heating2: 61 percent / potassium carbonate / acetone / 6 h  

Multi-step reaction with 2 steps 1: 49 percent / titanium(IV) chloride / CH2Cl2 / 1 h / -10 °C2: 96 percent / sodium chlorite, resorcinol / dioxane / 24 h / pH 4.4