[摘要]：Treatment of N-arylisonicotinamides with trifluoromethanesulfonic anhydride triggers intramol. nucleophilic attack of the aryl ring on the 4-position of the pyridinium intermediate. The products are spirocyclic dihydropyridines, e.g. I, which can be converted to valuable spirocyclic piperidines related to biol. active mols.
