carbon tetrabromide; triphenylphosphine in dichloromethane T=20°C; 63 h;

sodium bromide in acetone 48 h; Heating / reflux;

1: With sodium tetrahydroborate in tetrahydrofuran T=5 - 10°C; 1 h; Inert atmosphere; 2: With AlCl3, aluminium chloride in tetrahydrofuran T=45 - 50°C; 4 h; Inert atmosphere;

1.1: toluene-4-sulfonic acid / methanol / 0.5 h / 0 - 5 °C 1.2: 6 h / 0 - 5 °C 2.1: sodium tetrahydroborate / tetrahydrofuran / 1 h / 5 - 10 °C / |Inert atmosphere 2.2: 4 h / 45 - 50 °C / |Inert atmosphere View Scheme

1.1: AlCl3, aluminium chloride / dichloromethane / 0.5 h / 0 - 5 °C / |Inert atmosphere 1.2: 0.5 h / 0 - 5 °C / |Inert atmosphere 2.1: toluene-4-sulfonic acid / methanol / 0.5 h / 0 - 5 °C 2.2: 6 h / 0 - 5 °C 3.1: sodium tetrahydroborate / tetrahydrofuran / 1 h / 5 - 10 °C / |Inert atmosphere 3.2: 4 h / 45 - 50 °C / |Inert atmosphere View Scheme

1: With potassium hydroxide; methyltriethyl ammonium chloride in water; toluene T=100°C; 15.25 h; 2: With hydrogen bromide in water; toluene Product distribution / selectivity;

1: With potassium hydroxide; methyltriethyl ammonium chloride in water; butanone T=75°C; 6 h; Heating / reflux; 2: With hydrogen bromide in water; butanone

potassium carbonate in acetonitrile 2 h; Heating / reflux;

potassium hydroxide in acetonitrile T=25 - 45°C; Product distribution / selectivity;