1: 1.) n-BuLi / 1.) THF, room temp., 16 h; 2.) THF, 15 deg C, 1.5 h 2: 54 percent / CH2CHOLi / tetrahydrofuran / 0.5 h / 60 °C View Scheme

sodium hydrogencarbonate; 3-chloro-benzenecarboperoxoic acid in dichloromethane