1: 14 g / Mg / diethyl ether / 1 h / Heating 2: 1.3 g / conc. and gaseous HCl / dioxane / 2 h / 55 - 65 °C 3: 0.45 g / selenium dioxide / xylene / 8 h / Heating 4: 1.) N-bromosuccinimide; 2.) triethylamine / 1.) CCl4, reflux, 2.5 h, irradiation; 2.) reflux, 6 h 5: 0.09 g / 57percent hydriodic acid / 3 h / Heating View Scheme