1: 78 percent / t-BuOOH / 2.) VO(acac)2 / benzene / 4 h / Ambient temperature 2: 63 percent / copper(I) iodide / diethyl ether / 4 h / 0 °C 3: 1.) N,N-dimethylformamide dimethyl acetale / 1.) rt., overnight; 2.) acetic anhydride, boiling, 8 h 4: 84 percent / LiNH2 / liquid ammonia; hexane / 0.5 h View Scheme