trichloroacetic acid in dichloromethane 0.0833333 h; Ambient temperature;

1: 76 percent / pyridine / 48 h / Ambient temperature 2: (diethylamino)sulfur trifluoride (DAST) / CH2Cl2 / 14 h / Ambient temperature 3: p-toluenesulfonic acid / CHCl3; methanol / 0.25 h / Ambient temperature View Scheme

1: (diethylamino)sulfur trifluoride (DAST) / CH2Cl2 / 14 h / Ambient temperature 2: p-toluenesulfonic acid / CHCl3; methanol / 0.25 h / Ambient temperature View Scheme