1: 89 percent / POCl3 / toluene 3: 100 percent / KOH / ethanol / 5 h / Ambient temperature 4: 34 percent / η5-cyclopentadienyl dicarbonyl cobalt / m-xylene / 8 h / Heating; Irradiation 5: 100 percent / trifluoroacetic acid / CCl4 / 1.5 h View Scheme

1: phosphorus pentachloride / dichloromethane / 1.5 h / 35 - 40 °C / |Inert atmosphere 2: diethyl ether / 20 °C / |Inert atmosphere 3: water / 20 °C 4: tetrahydrofuran / 72 h / 40 °C / |Inert atmosphere 5: potassium hexamethylsilazane / tetrahydrofuran / 0 °C / |Inert atmosphere 6: sodium cyanoborohydride / ethanol; tetrahydrofuran / 13 h / 0 - 20 °C / |Inert atmosphere 7: palladium 10 on activated carbon; hydrogen / methanol / 2 h / 20 °C / |Inert atmosphere View Scheme

1,3-benzene disulfonyl dichloride; triethylamine in dichloromethane T=110°C; 5 h;

PPA in dichloromethane T=50°C; 2 h;

1: 53 percent / polyphosphoric acid / CH2Cl2 / 2 h / 50 °C 2: 82 percent / pTsOH / 1,2-dichloro-ethane / 0.5 h / Heating 3: polyphophoric acid / 80 - 100 °C View Scheme