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