1: With hydrogen bromide; sodium nitrite in ethanol; water T=0°C; 0.25 h; 2: With hydrogen bromide; copper(I) bromide in ethanol; water T=95°C; Sandmeyer-type reaction; 0.25 h;

chromium(VI) oxide; acetic acid in water T=20°C; 12 h;

1.1: ethanol / 16 h / 20 °C 2.1: potassium permanganate; MgSO4 / acetone; H2O / 2.25 h / 20 °C 3.1: 9.11 g / aq. HCl / 3 h / 90 °C 4.1: HBr; NaNO2 / ethanol; H2O / 0.25 h / 0 °C 4.2: 70 percent / CuBr; HBr / ethanol; H2O / 0.25 h / 95 °C View Scheme

1: 34 percent / n-BuLi; TMEDA / pentane; hexane / -78 - 20 °C 2: 41 percent / CrO3; AcOH / H2O / 12 h / 20 °C View Scheme

1.1: potassium permanganate; MgSO4 / acetone; H2O / 2.25 h / 20 °C 2.1: 9.11 g / aq. HCl / 3 h / 90 °C 3.1: HBr; NaNO2 / ethanol; H2O / 0.25 h / 0 °C 3.2: 70 percent / CuBr; HBr / ethanol; H2O / 0.25 h / 95 °C View Scheme

1.1: 9.11 g / aq. HCl / 3 h / 90 °C 2.1: HBr; NaNO2 / ethanol; H2O / 0.25 h / 0 °C 2.2: 70 percent / CuBr; HBr / ethanol; H2O / 0.25 h / 95 °C View Scheme

1: 62 percent / diethyl ether / 140 h / 40 °C 2: 40 percent / K3PO4; Pd(dba)2; bis[2-(diphenylphosphino)phenyl] ether / toluene / 24 h / 110 °C View Scheme