pyridine; thionyl bromide in toluene T=80°C; 4 h;

1: Et3N / diethyl ether 2: diethyl ether 3: SOBr2; pyridine / toluene / 4 h / 80 °C View Scheme

1.1: 99 percent / K2CO3 / dimethylformamide / 24 h / 65 °C 2.1: 97 percent / Dess-Martin periodinane / CH2Cl2 / 1.33 h 3.1: NaHSO3 / ethyl acetate; H2O / 1 h 3.2: 89 percent / H2O / 48 h 4.1: Et3N / diethyl ether 5.1: diethyl ether 6.1: SOBr2; pyridine / toluene / 4 h / 80 °C View Scheme

1.1: NaHSO3 / ethyl acetate; H2O / 1 h 1.2: 89 percent / H2O / 48 h 2.1: Et3N / diethyl ether 3.1: diethyl ether 4.1: SOBr2; pyridine / toluene / 4 h / 80 °C View Scheme

1.1: 97 percent / Dess-Martin periodinane / CH2Cl2 / 1.33 h 2.1: NaHSO3 / ethyl acetate; H2O / 1 h 2.2: 89 percent / H2O / 48 h 3.1: Et3N / diethyl ether 4.1: diethyl ether 5.1: SOBr2; pyridine / toluene / 4 h / 80 °C View Scheme

1.1: 99 percent / K2CO3 / dimethylformamide / 24 h / 65 °C 2.1: 97 percent / Dess-Martin periodinane / CH2Cl2 / 1.33 h 3.1: NaHSO3 / ethyl acetate; H2O / 1 h 3.2: 89 percent / H2O / 48 h 4.1: Et3N / diethyl ether 5.1: diethyl ether 6.1: SOBr2; pyridine / toluene / 4 h / 80 °C View Scheme