1.1: phosphorus tribromide / tetrahydrofuran / 3 h / 0 °C / |Inert atmosphere 2.1: N,N-dimethyl-formamide / 18 h / 20 °C / |Darkness 3.1: potassium tert-butylate / tetrahydrofuran; N,N-dimethyl-formamide / 2.67 h / -78 °C 3.2: -78 - 20 °C 4.1: sodium hydroxide; water / methanol / 1 h / 20 °C / pH 12 5.1: phosphorus tribromide / tetrahydrofuran / 0.5 h / 0 °C / |Inert atmosphere; |Cooling with acetone-dry ice 6.1: sodium hexamethyldisilazane / tetrahydrofuran; N,N-dimethyl-formamide / 0.5 h / -20 - 0 °C / |Inert atmosphere; |Cooling with acetone-dry ice 7.1: Pd(1,2-bis(diphenylphosphino)ethane)Cl2 / tetrahydrofuran / 0.08 h / 0 °C / |Cooling with acetone-dry ice; |Inert atmosphere 7.2: 4.5 h / 0 °C / |Inert atmosphere 8.1: ammonium cerium (IV) nitrate / water; dichloromethane; acetonitrile / 0.25 h / 0 °C View Scheme

1: 100 percent / Ph3P, I2, imidazole / diethyl ether; acetonitrile / 0.5 h / Ambient temperature 2: 39 percent / LiN(SiMe3)2 / tetrahydrofuran / -78 °C / 1.) 40 min, 2.) 2 h 3: 50 percent / n-Bu4NF / H2O; tetrahydrofuran / 15 h / Ambient temperature 4: 100 percent / K2CO3 / methanol / 2 h / Ambient temperature View Scheme