trifluoroacetic acid in dichloromethane T=20°C; 20 h; Inert atmosphere;

1.1: NaH / dimethylformamide / 0.17 h / 0 °C 1.2: 74 percent / dimethylformamide / 5 h / 20 °C 2.1: trifluoroacetic acid / CH2Cl2 / 1 h / 20 °C 3.1: 1.95 g / Et3N; 1-hydroxybenzotriazole hydrate; water soluble carbodiimide hydrochloride / CH2Cl2 / 18 h / 20 °C 4.1: trifluoroacetic acid / CH2Cl2 / 1 h / 20 °C 5.1: 2.6 g / Et3N; 1-hydroxybenzotriazole hydrate; water soluble carbodiimide hydrochloride / CH2Cl2 / 18 h / 20 °C 6.1: trifluoroacetic acid / CH2Cl2 / 1 h / 20 °C 7.1: 411 mg / Et3N; 1-hydroxybenzotriazole hydrate; water soluble carbodiimide hydrochloride / dimethylformamide / 18 h / 20 °C 8.1: 96 percent / H2 / 10 percent Pd/C / dimethylformamide / 18 h / 20 °C 9.1: 75 percent / Et3N; SO3*pyridine / dimethylsulfoxide / 1 h / 20 °C 10.1: 2.3 mg / NaBH4 / methanol / 2 h / 20 °C 11.1: 6N HCl / 18 h / 105 °C View Scheme

sulfur trioxide pyridine complex; dimethyl sulfoxide; triethylamine in dichloromethane T=20°C; 0.5 h;