1.1: 82 percent / triphenylphosphine; diisopropyl azodicarboxylate / tetrahydrofuran / 0 - 20 °C 2.1: tristrimethylsilylsilane; azoisobutyronitrile / toluene / 12 h / Heating 2.2: 74 percent / p-toluenesulfonic acid / toluene / 2 h / Heating 3.1: 85 percent / hydrazine monohydrate / ethanol / 3 h / Heating 4.1: 84 percent / KOH / methanol / 9 h / Heating View Scheme

1.1: 82 percent / triphenylphosphine; diisopropyl azodicarboxylate / tetrahydrofuran / 0 - 20 °C 2.1: tristrimethylsilylsilane; azoisobutyronitrile / toluene / 12 h / Heating 2.2: 74 percent / p-toluenesulfonic acid / toluene / 2 h / Heating 3.1: 85 percent / hydrazine monohydrate / ethanol / 3 h / Heating 4.1: 84 percent / KOH / methanol / 9 h / Heating 5.1: 90 percent / 18 h / 20 °C View Scheme