1: 4-(N,N-dimethlyamino)pyridine; triethylamine / dichloromethane / 4 h / 80 °C / Inert atmosphere 2: tetrabutyl ammonium fluoride / tetrahydrofuran / 6 h / 0 - 20 °C / Inert atmosphere 3: 4-(N,N-dimethlyamino)pyridine; triethylamine; 2,4,6-trichlorobenzoyl chloride / toluene / 1 h / 0 - 20 °C / Inert atmosphere 4: tetrabutyl ammonium fluoride; acetic acid / tetrahydrofuran / 4 h / 0 - 20 °C / Inert atmosphere View Scheme