in dimethyl sulfoxide T=70°C; 16 h;

1: aq. ethanol / 2 h / 0 °C 2: 95 percent / NaH / 1,2-dimethoxy-ethane / 1 h / 0 °C 3: 1.) O3 2.) Me2S / 1.) MeOH, CH2Cl2, -78 deg C, 1h 2.) -78 deg C --> RT 4: NaH / dimethylformamide / 30 °C 5: 80 percent / 2N aq. HCl / tetrahydrofuran / 5 h / Heating 6: 79 percent / dimethylsulfoxide / 16 h / 70 °C View Scheme

1: Ac2O / 2 h / 145 °C 2: aq. ethanol / 2 h / 0 °C 3: 95 percent / NaH / 1,2-dimethoxy-ethane / 1 h / 0 °C 4: 1.) O3 2.) Me2S / 1.) MeOH, CH2Cl2, -78 deg C, 1h 2.) -78 deg C --> RT 5: NaH / dimethylformamide / 30 °C 6: 80 percent / 2N aq. HCl / tetrahydrofuran / 5 h / Heating 7: 79 percent / dimethylsulfoxide / 16 h / 70 °C View Scheme