1: 69 percent / tetrahydrofuran / 0.33 h / 0 °C 2: 20 percent / NaH / dioxane / Ambient temperature 3: 1.) pyridinium 3-nitrobenzenesulfonic acid, 2.) AcOH / 1.) H2O, reflux, 3 h, 2.) reflux, 1 h 4: 26 percent / H2, Et3N / 10percent Pd/C / ethyl acetate / 3 h / 2585.7 Torr View Scheme