1: With hydrogenchloride in water 2: With thionyl chloride Further stages.;

oxalyl dichloride in dichloromethane

1: 90 percent / BuLi / hexane; tetrahydrofuran / 1.) -70 deg C, 30 min, 2.) warm to room temperature 2: 65 percent / conc. HCl / 14 h / Heating 3: oxalyl chloride / CH2Cl2 View Scheme