tetrabutyl ammonium fluoride in tetrahydrofuran T=20°C;

4-(N,N-dimethlyamino)pyridine; dicyclohexyl-carbodiimide in benzene T=20°C;

1: 59 percent / Et3N / ethyl acetate / 1 h / Heating 2: 93 percent / N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine / benzene / 20 °C View Scheme