1: 1.) n-BuLi / 1.) THF, -78 deg C, 2.) 1 h, -78 deg C to r. t. 2: 73 percent / oxygen, CuCl / PdCl2 / dimethylformamide; H2O / 12 h / Ambient temperature 3: DBU / CH2Cl2 / 1 h / Heating 4: 85 percent / H2SO4 / acetic acid; diethyl ether / 1.5 h / 0 °C View Scheme

1: 1.) n-BuLi / 1.) THF, -78 deg C, 2.) 1 h, -78 deg C to r. t. 2: 73 percent / oxygen, CuCl / PdCl2 / dimethylformamide; H2O / 12 h / Ambient temperature 3: DBU / CH2Cl2 / 1 h / Heating View Scheme