Insertion of sulfur trioxide into allylic CF bonds of both terminal and internal fluoro olefins is shown to form the most stable olefinic products. A mechanism involving fluoroallyl cations as intermediates is proposed. State-of-the-art ab initio calculations of the ground-state energies for two isomeric unsaturated fluoro ethers establish the slightly greater stability (5.7 kcal/mol) of a vinyl ether over the corresponding fluoro olefin. A description of the optimized ...
