1: 1,8-diazabicyclo<5.4.0>undec-7-ene / CH2Cl2 / 3 h / 0 - 20 °C 2: 96 percent / base / H2O 3: 68 percent / oxalyl chloride / benzene / 1.) 0 deg C, 0.5 h, 2.) 70 deg C, 1 h View Scheme