1: 17 percent / potassium tert-butoxide / CH2Cl2 / 4 h / -78 - 20 °C 2: CF3COOH / CH2Cl2 3: acetone / 35 °C View Scheme

Multi-step reaction with 3 steps 1: 96.5 percent / 2 N NaOH / dioxane / 0.67 h2: 52 percent / N-methylmorpholine, 1-hydroxybenzotriazole (HOBt), 1-<3-(dimethylamino)propyl>-3-ethylcarbodiimide hydrochloride (EDC) / tetrahydrofuran / 1.) 0 deg C, 1 h, 2.) RT, overnight3: 99 percent / H2 / 10percent Pd/C / methanol / 3 h / 2275.5 Torr