bromine in N,N-dimethyl-formamide

sodium tetrahydroborate; N,N,N',N,-tetramethylethylenediamine; palladium diacetate; triphenylphosphine in tetrahydrofuran T=20°C; 18 h; Inert atmosphere; regioselective reaction;

1: With bromine in tetrachloromethane 2 h; 2: With sodium hydride in methanol 2 h; Heating; Further stages.;

1: pyridine / dichloromethane / 1 h / 0 - 20 °C / |Inert atmosphere 2: bromine / tetrachloromethane / 4.5 h / 20 °C / |Inert atmosphere 3: palladium diacetate; triphenylphosphine; N,N,N',N,-tetramethylethylenediamine; sodium tetrahydroborate / tetrahydrofuran / 1.25 h / 20 °C / |Inert atmosphere 4: palladium diacetate; triphenylphosphine; N,N,N',N,-tetramethylethylenediamine; sodium tetrahydroborate / tetrahydrofuran / 18 h / 20 °C / |Inert atmosphere View Scheme

1: bromine / tetrachloromethane / 4.5 h / 20 °C / |Inert atmosphere 2: palladium diacetate; triphenylphosphine; N,N,N',N,-tetramethylethylenediamine; sodium tetrahydroborate / tetrahydrofuran / 1.25 h / 20 °C / |Inert atmosphere 3: palladium diacetate; triphenylphosphine; N,N,N',N,-tetramethylethylenediamine; sodium tetrahydroborate / tetrahydrofuran / 18 h / 20 °C / |Inert atmosphere View Scheme