1.1: 97 percent / H2 / Pd-C / aq. ethanol / 12 h / 2585.81 Torr 2.1: conc. HBr; NaNO2 / H2O / 0 - 5 °C 2.2: 81 percent / CuBr; conc. HBr / H2O / 0.17 h / 100 °C 3.1: 99 percent / DIBAL / toluene / -78 - 0 °C 4.1: 95 percent / PCC; 4 Angstroem molecular sieves / CH2Cl2 / 10 h View Scheme