1: 54 percent / dimethylethylene urea; t-BuOK / toluene / Heating 2: 83 percent / 2,6-lutidine; dilauroyl peroxide / cyclohexane / Heating 3: 92 percent / Bu3SnH; AIBN / toluene / 2.5 h / Heating 4: 57 percent / oxalic acid; silica gel 5: 93 percent / AcOH; AcONH4; air / 1.5 h / Heating View Scheme