1: 2-bromo-4-phenyl thiophene With magnesium in tetrahydrofuran 7 h; Heating; 2: boric acid trimethyl ester in tetrahydrofuran T=-78 - 20°C; 3: With hydrogenchloride in tetrahydrofuran T=20°C; 2 h; Further stages.;

1.1: 73 percent / Br2 / acetic acid / 5 h / Heating 2.1: Mg / tetrahydrofuran / 7 h / Heating 2.2: tetrahydrofuran / -78 - 20 °C 2.3: 73 percent / aq. HCl / tetrahydrofuran / 2 h / 20 °C View Scheme

1.1: tetrakis(triphenylphosphine)palladium(0) / 1,2-dimethoxy-ethane / 0.17 h / 20 °C 1.2: 64 percent / aq. Na2CO3 / 24 h / Heating 2.1: 73 percent / Br2 / acetic acid / 5 h / Heating 3.1: Mg / tetrahydrofuran / 7 h / Heating 3.2: tetrahydrofuran / -78 - 20 °C 3.3: 73 percent / aq. HCl / tetrahydrofuran / 2 h / 20 °C View Scheme