ozone in methanol T=-78 - 20°C;

Multi-step reaction with 2 steps 1: 85 percent / aluminum chloride / CH2Cl2 / 1 h / 0 °C2: 1.) N-bromosuccinimide (NBS), AIBN, 2.) NaI / 1.) carbon tetrachloride, 12 h, reflux, 2.) acetone, 2 h, reflux  

Multi-step reaction with 4 steps 1: CH2Cl2 / 1 h / -78 °C / Irradiation2: potassium carbonate / ethane-1,2-diol / 4 h / 120 °C3: 85 percent / aluminum chloride / CH2Cl2 / 1 h / 0 °C4: 1.) N-bromosuccinimide (NBS), AIBN, 2.) NaI / 1.) carbon tetrachloride, 12 h, reflux, 2.) acetone, 2 h, reflux  

Multi-step reaction with 4 steps 1: 51 percent / CH2Cl2 / 1 h / -78 °C / Irradiation2: potassium carbonate / ethane-1,2-diol / 4 h / 120 °C3: 85 percent / aluminum chloride / CH2Cl2 / 1 h / 0 °C4: 1.) N-bromosuccinimide (NBS), AIBN, 2.) NaI / 1.) carbon tetrachloride, 12 h, reflux, 2.) acetone, 2 h, reflux