1: 93 percent / 3-chloroperoxybenzoic acid / CH2Cl2 / 5 h / 0 °C 2: 60 percent / sodium formate / 70-75 deg C for 3 h then room temperature for 1 h View Scheme

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