Camophorsulfone-imine (5): (3aS,6S)-8,8-dimethyl-4,5,6,7tetrahydro-3H-3a,6-methanobenzo[c]isothiazole 2,2-dioxide. A 100 ml three-neck round-bottom flask, fitted with a thermometer ,an isobaric dropping funnel and a condenser fitted with a CaCl 2 guard and connected to two wash bottles, the 2 nd of which contains a 10% Sodium hydroxide solution, are introduced (23.23g, 0.1 mol) of camphorsulfonic acid. camphorsulfonic acid. Afterwards, to this solid is added (14,5 ml, 0.2 mol) of SOCl 2 dropwise. The reaction mixture is heated to 115 • C until the evolution of gas ceases (about 53 minutes 1 and 46 mins 2 ). In the first essay 1 , the condenser is replaced by a distillation column. The remaining traces of SOCl 2 are removed by co-distillation with toluene (20 ml) for 30 mins (boiling point is 110°C). This leads to a dark brown liquid. As the desired product should have a light white color, we decided to redo this first step of chlorination. Surprisingly, this time we had a white to yellowish coloration and results were much better in the second essay 2 which has been carried out without distillation with toluene. It has been thought that we had a degradation or a polymerization of the product during the first essay. The reaction is followed by TLC. At the end of this step, a yellowish mass is obtained in suspension in a solution which will be dissolved in 1,4-dioxane. H NMR (400 MHz, CDCl 3 ) δ 3.04 (dd, J = 86.0, 13.4 Hz, 2H), 2.72 (ddd, J = 19.4, 4.4, 2.3 Hz, 0.97H), 2.34 (d, J = 19.4 Hz, 1H), 2.22 (t, J = 4.1 Hz, 0.95H), 2.10 -1.96 (m, 2H), 1.75 -1.38 (m, 2H), 1.04 (s, 3H), 0.82 (s, 2.93H).