Multi-step reaction with 5 steps 1: potassium acetate / 4 h / 160 - 180 °C2: palladium 10 on activated carbon; hydrogen / ethyl acetate / 15 h / 20 °C / 760.05 Torr3: thionyl chloride / tetrachloromethane / 3 h / Reflux4: boron trifluoride / acetonitrile / 8 h / Reflux5: bromine / tetrachloromethane / 2 h / 20 °C / Darkness