1: BuLi, N,N'-dimethyl-N,N'-propyleneurea / hexane; tetrahydrofuran / 1.) -78 deg C, 1 h; 2.) -50 deg C, 1 h 2: 75.5 percent / KOH / diethyl ether; methanol / 1 h / Ambient temperature 3: 52 percent / Na, dibenzo<18>crown-6 / liquid ammonia; tetrahydrofuran / 0.03 h View Scheme