1.1: 87 percent / KOH / ethanol / 72 h / 20 °C 2.1: 70 percent / p-TsOH / benzene / Heating 3.1: 71 percent / LHMDS / tetrahydrofuran / 5 h / -75 °C 4.1: BH3*Me2S / diethyl ether / 5 h / Heating 4.2: 88 percent / aq. HCl / diethyl ether / 3 h / Heating 5.1: 98 percent / H2 / Pd/C / ethanol / 20 h / 20 °C View Scheme