1: 98 percent / chromic acid / diethyl ether / 3 h / Ambient temperature 2: 42 percent / diethyl ether; cyclohexane / 1.) -70 deg C, 10 min, 2.) 20 deg C, 20 min 3: 1.) sodium azide, trifluoroacetic acid, 2. ) LAH / 1.) CHCl3, room temperature, 4 h, 2.) ether, reflux, 3 h 4: 86 percent / K2CO3 / dimethylformamide / 48 h / 60 °C View Scheme

Multi-step reaction with 3 steps 1: 98 percent / chromic acid / diethyl ether / 3 h / Ambient temperature2: 42 percent / diethyl ether; cyclohexane / 1.) -70 deg C, 10 min, 2.) 20 deg C, 20 min3: 1.) sodium azide, trifluoroacetic acid, 2. ) LAH / 1.) CHCl3, room temperature, 4 h, 2.) ether, reflux, 3 h