1: T=0°C; 2: With hydrogen bromide; acetic acid T=65°C; 24 h; Further stages.;

phosphorus tribromide in benzene T=45°C; 6 h;

1: 95 percent / triethylbenzylammonium chloride; aq. NaOH / dimethylsulfoxide / 5 h / 20 °C 2: 99 percent / PdCl2; Et3N; PPh3 / 5 h / 150 °C 3: 89 percent / DIBAL / tetrahydrofuran / 3 h / -78 °C 4: 97 percent / PBr3 / benzene / 6 h / 45 °C View Scheme

1: 95 percent / triethylbenzylammonium chloride; aq. NaOH / dimethylsulfoxide / 5 h / 20 °C 2: 99 percent / PdCl2; Et3N; PPh3 / 5 h / 150 °C 3: 89 percent / DIBAL / tetrahydrofuran / 3 h / -78 °C 4: 97 percent / PBr3 / benzene / 6 h / 45 °C View Scheme

1: 99 percent / PdCl2; Et3N; PPh3 / 5 h / 150 °C 2: 89 percent / DIBAL / tetrahydrofuran / 3 h / -78 °C 3: 97 percent / PBr3 / benzene / 6 h / 45 °C View Scheme

1: 89 percent / DIBAL / tetrahydrofuran / 3 h / -78 °C 2: 97 percent / PBr3 / benzene / 6 h / 45 °C View Scheme

1.1: n-BuLi / tetrahydrofuran / -78 °C 1.2: 100 percent / tetrahydrofuran / 12 h / -78 - 20 °C 2.1: 0 °C 2.2: 88 percent / HBr; acetic acid / 24 h / 65 °C View Scheme