trifluoromethanesulfonic acid anhydride Dehydration;

1: 80 percent / aq. H2SO4 / toluene / 12 h / Heating; Dean-Stark-conditions 2: 71 percent / phosgene; NEt3 / CH2Cl2 / 1 h / 0 °C View Scheme

trifluoromethylsulfonic anhydride; i-PrNEt; 3,3-dimethyldioxirane 1.) CH2Cl2, -40 deg C; 2.) -78 deg C; Yield given. Multistep reaction. Yields of byproduct given;