1: N-chloro-succinimide / dichloromethane / 3 h / 0 - 20 °C / Inert atmosphere 2: potassium permanganate / acetone / 0.5 h / Inert atmosphere; Reflux View Scheme

N-chloro-succinimide in dichloromethane T=0 - 20°C; 3 h; Inert atmosphere;