1: 6.5 g / sodium azide / dioxane; H2O / Ambient temperature 2: toluene / 3 h / Heating 3: 80 percent / 3 h / Heating 4: 1.) sodium, liquid ammonia, 2.) pyridine / 1.) methanol, 2.) CH2Cl2, 0 deg C, 2 h 5: 1.) butyl-lithium / 1.) DMF, hexane, room temperature, 1 h, 2.) ether View Scheme

1: 6.5 g / sodium azide / dioxane; H2O / Ambient temperature 2: toluene / 3 h / Heating 3: 80 percent / 3 h / Heating 4: 1.) sodium, liquid ammonia, 2.) pyridine / 1.) methanol, 2.) CH2Cl2, 0 deg C, 2 h View Scheme