1: 1.) NaOMe / 1.) DMSO, RT, 10 min, 2.) DMSO, 6 h 2: 88 percent / p-TsOH / benzene / 72 h / Heating 3: 61 percent / BuLi / tetrahydrofuran; hexane; diethyl ether / 2.5 h / -78 - 20 °C 4: 98 percent / Fe2(CO)9 / benzene / 4 h / Heating 5: 100 percent / 2 M aq. HClO4 / CH2Cl2 / 5 h / Ambient temperature 6: 75 percent / diethyl ether / 0.25 h / Ambient temperature 7: 15 percent / AgO, 6 M aq. HNO3 / dioxane / 0.25 h / Ambient temperature 8: 56 percent / H2SO4 / ethanol / 0.5 h / Heating View Scheme

Multi-step reaction with 5 steps 1: 1.) NaOMe / 1.) DMSO, RT, 10 min, 2.) DMSO, 6 h2: 88 percent / p-TsOH / benzene / 72 h / Heating3: 61 percent / BuLi / tetrahydrofuran; hexane; diethyl ether / 2.5 h / -78 - 20 °C4: 98 percent / Fe2(CO)9 / benzene / 4 h / Heating5: 100 percent / 2 M aq. HClO4 / CH2Cl2 / 5 h / Ambient temperature  

Multi-step reaction with 6 steps 1: 1.) NaOMe / 1.) DMSO, RT, 10 min, 2.) DMSO, 6 h2: 88 percent / p-TsOH / benzene / 72 h / Heating3: 61 percent / BuLi / tetrahydrofuran; hexane; diethyl ether / 2.5 h / -78 - 20 °C4: 98 percent / Fe2(CO)9 / benzene / 4 h / Heating5: 100 percent / 2 M aq. HClO4 / CH2Cl2 / 5 h / Ambient temperature6: 75 percent / diethyl ether / 0.25 h / Ambient temperature