toluene-4-sulfonic acid in dichloromethane T=35°C; 0.5 h;

1: 70 percent 2: n-BuLi / 1.) THF, ether, -90 deg C, 0.5 h; 2.) -75 deg C 3: 79 percent / N(Et)3, 2,4-Dinitrobenzenesulfenyl chloride / CH2Cl2 / 0.75 h / Heating 4: m-Chloroperbenzoic acid (85percent) / CCl4 / 0.17 h / 20 - 30 °C 5: NBS, Dibenzoyl peroxide / CCl4 / 7 h / Heating 6: Benzyltriethylammonium chloride / acetonitrile / 22 h / 30 °C 7: 1.) t-BuOCl; 2.) DBU / 1.) CCl4, 4 h, reflux, irradiation; 2.) CH2Cl2, 30 deg C, 2 h 8: p-TsOH / CH2Cl2 / 0.5 h / 35 °C View Scheme

1: n-BuLi / 1.) THF, ether, -90 deg C, 0.5 h; 2.) -75 deg C 2: 79 percent / N(Et)3, 2,4-Dinitrobenzenesulfenyl chloride / CH2Cl2 / 0.75 h / Heating 3: m-Chloroperbenzoic acid (85percent) / CCl4 / 0.17 h / 20 - 30 °C 4: NBS, Dibenzoyl peroxide / CCl4 / 7 h / Heating 5: Benzyltriethylammonium chloride / acetonitrile / 22 h / 30 °C 6: 1.) t-BuOCl; 2.) DBU / 1.) CCl4, 4 h, reflux, irradiation; 2.) CH2Cl2, 30 deg C, 2 h 7: p-TsOH / CH2Cl2 / 0.5 h / 35 °C View Scheme

1: m-Chloroperbenzoic acid (85percent) / CCl4 / 0.17 h / 20 - 30 °C 2: NBS, Dibenzoyl peroxide / CCl4 / 7 h / Heating 3: Benzyltriethylammonium chloride / acetonitrile / 22 h / 30 °C 4: 1.) t-BuOCl; 2.) DBU / 1.) CCl4, 4 h, reflux, irradiation; 2.) CH2Cl2, 30 deg C, 2 h 5: p-TsOH / CH2Cl2 / 0.5 h / 35 °C View Scheme

1: 79 percent / N(Et)3, 2,4-Dinitrobenzenesulfenyl chloride / CH2Cl2 / 0.75 h / Heating 2: m-Chloroperbenzoic acid (85percent) / CCl4 / 0.17 h / 20 - 30 °C 3: NBS, Dibenzoyl peroxide / CCl4 / 7 h / Heating 4: Benzyltriethylammonium chloride / acetonitrile / 22 h / 30 °C 5: 1.) t-BuOCl; 2.) DBU / 1.) CCl4, 4 h, reflux, irradiation; 2.) CH2Cl2, 30 deg C, 2 h 6: p-TsOH / CH2Cl2 / 0.5 h / 35 °C View Scheme

1: NBS, Dibenzoyl peroxide / CCl4 / 7 h / Heating 2: Benzyltriethylammonium chloride / acetonitrile / 22 h / 30 °C 3: 1.) t-BuOCl; 2.) DBU / 1.) CCl4, 4 h, reflux, irradiation; 2.) CH2Cl2, 30 deg C, 2 h 4: p-TsOH / CH2Cl2 / 0.5 h / 35 °C View Scheme

1: 1.) t-BuOCl; 2.) DBU / 1.) CCl4, 4 h, reflux, irradiation; 2.) CH2Cl2, 30 deg C, 2 h 2: p-TsOH / CH2Cl2 / 0.5 h / 35 °C View Scheme

1: Benzyltriethylammonium chloride / acetonitrile / 22 h / 30 °C 2: 1.) t-BuOCl; 2.) DBU / 1.) CCl4, 4 h, reflux, irradiation; 2.) CH2Cl2, 30 deg C, 2 h 3: p-TsOH / CH2Cl2 / 0.5 h / 35 °C View Scheme