Treatment of semicyclic 3-trifloxypropene iminium triflates 4a -c,e,f, in which the iminium function is part of a six-membered ring, with a polymer-supported tertiary amine leads to 3- [(trifluoromethyl)sulfonyl]-1,4,5,6-tetrahydropyridines 7.Related five- and seven-membered cyclic iminium salts do not react to give the corresponding enaminosulfones.