1: 95 percent / m-chloroperoxybenzoic acid (m-CPBA) / CH2Cl2 / 5 h / 0 °C 2: 56 percent / sodium formate / 1) 70-75 deg C, 3 h, 2) room temp., 1 h 3: 1) THF, -78 - 0 deg C, 2) CDCl3, 140 deg C, 1 h View Scheme

Multi-step reaction with 2 steps 1: 94 percent / MCPBA / CH2Cl2 / 5 h / 0 °C2: 56 percent / HCO2Na / 3 h / 70 - 75 °C  

With  3-chloro-benzenecarboperoxoic acid in  dichloromethane T=0°C; 5 h;