1: H2 / Pd/C / methanol / 15 h / Ambient temperature 2: aq. NaOH / tetrahydrofuran / 0.5 h / 0 °C 3: 79 percent / BBr3 / CH2Cl2 / 2 h / -78 - 20 °C 4: triphenylphosphine, diethyldiazodicarboxylate / tetrahydrofuran / 28 h / Ambient temperature View Scheme