In a reflux set-up, camphorsultam, trans-crotonyl chloride and copper chloride CuCl 2 are introduced. The reflux set-up is placed under argon gas. The CuCl 2 is first dried under vacuum. Water reacts with the acid chloride, hence precautions should be seriously taken. In fact, the crude should be kept under laboratory hood at all times (we had a bad smell in the laboratory during the evaporation phase using the rotatory evaporator, which became an inconvenience to our surrounding). The reflux is maintained for 1 h at 80 • C. The reaction mixture is filtered to remove the remaining CuCl 2 and then recrystallised with methanol. The copper complex here acts as a catalyst for the reaction by complexing on the oxygen of the acid chloride. The yield of this step is 11%. This low yield is due to the fact that only a small portion of the synthesized crude was concentrated and purified, in order not to become an inconvenience to our surrounding.