1: 79 percent / DCC; DMAP; DMAP*HCl / CH2Cl2 / Heating 2: 66 percent / selenium dioxide; AcOH / dioxane / 3 h / 80 °C 3: 73 percent / boron trifluoride diethyl etherate / CH2Cl2 / 5 h / -20 °C 4: 49 percent / methylamine / CH2Cl2; methanol / 9 h / -20 °C 5: 44 percent / 1,4-cyclohexadiene / Pd/C / dimethylformamide; ethanol / 10 h / 40 °C View Scheme