1: 10percent aq. HCl / tetrahydrofuran / 0.33 h / 45 - 55 °C 2: Ag2CO3/Celite / toluene / 2 h / 95 °C View Scheme

Multi-step reaction with 6 steps 1: 87 percent / pyridine / 1 h / 25 °C2: toluene / 7 h / Irradiation3: imidazole / dimethylformamide / 23 °C4: 1.) O3, 2.) dimethyl sulfide / 1.) methanol5: CH2Cl2 / 18 h  

Multi-step reaction with 4 steps 1: imidazole / dimethylformamide / 23 °C2: 1.) O3, 2.) dimethyl sulfide / 1.) methanol3: CH2Cl2 / 18 h  

Multi-step reaction with 3 steps 1: 1.) O3, 2.) dimethyl sulfide / 1.) methanol2: CH2Cl2 / 18 h  

Multi-step reaction with 5 steps 1: toluene / 7 h / Irradiation2: imidazole / dimethylformamide / 23 °C3: 1.) O3, 2.) dimethyl sulfide / 1.) methanol4: CH2Cl2 / 18 h