1: iodine; silver trifluoroacetate / chloroform / 3 h / |Inert atmosphere 2: bis-triphenylphosphine-palladium(II) chloride; potassium carbonate / tetrahydrofuran / 20 °C / |Inert atmosphere 3: pyridine; potassium permanganate / water / |Reflux 4: oxalyl dichloride; N,N-dimethyl-formamide / dichloromethane / 2 h / 0 °C 5: dichloromethane / 20 °C 6: caesium carbonate; copper(I) thiophene-2-carboxylate; N,N,N',N,-tetramethylethylenediamine / water / 0.17 h / 300 °C / 12929 Torr / |Microwave irradiation 7: boron tribromide / dichloromethane / 0 °C / |Inert atmosphere View Scheme

1: bis-triphenylphosphine-palladium(II) chloride; potassium carbonate / tetrahydrofuran / 20 °C / |Inert atmosphere 2: pyridine; potassium permanganate / water / |Reflux 3: oxalyl dichloride; N,N-dimethyl-formamide / dichloromethane / 2 h / 0 °C 4: dichloromethane / 20 °C 5: caesium carbonate; copper(I) thiophene-2-carboxylate; N,N,N',N,-tetramethylethylenediamine / water / 0.17 h / 300 °C / 12929 Torr / |Microwave irradiation 6: boron tribromide / dichloromethane / 0 °C / |Inert atmosphere View Scheme

1: pyridine; potassium permanganate / water / |Reflux 2: oxalyl dichloride; N,N-dimethyl-formamide / dichloromethane / 2 h / 0 °C 3: dichloromethane / 20 °C 4: caesium carbonate; copper(I) thiophene-2-carboxylate; N,N,N',N,-tetramethylethylenediamine / water / 0.17 h / 300 °C / 12929 Torr / |Microwave irradiation 5: boron tribromide / dichloromethane / 0 °C / |Inert atmosphere View Scheme

1: caesium carbonate; copper(I) thiophene-2-carboxylate; N,N,N',N,-tetramethylethylenediamine / water / 0.17 h / 300 °C / 12929 Torr / |Microwave irradiation 2: boron tribromide / dichloromethane / 0 °C / |Inert atmosphere View Scheme

boron tribromide; acetic acid 1) CH2Cl2, overnight, 2) reflux, 24 h; Yield given. Multistep reaction;

1.1: sodium hydroxide / water / 1 h / |Reflux 1.2: 0.5 h / |Reflux 2.1: boron tribromide / dichloromethane / 18 h / 0 - 20 °C 2.2: 3 h / |Reflux View Scheme

anschliessendes Erhitzen mit Resorcin, wss, Natronlauge und wenig Kupfer(II)-sulfat;