1: 74 percent / pyridine 2: 91 percent / 1.5 h / 190 °C / 0.5 Torr / Heating 3: 1.) t-BuLi, 2.) BF3*OEt2 / 1.) THF, pentane, -78 deg C, 1 h, 2.) THF, pentane, ether, -78 deg C, 30 min, then -10 deg C, 30 min 4: 35 percent / pyridinium p-toluenesulfonate / benzene / Ambient temperature View Scheme