The azobisisobutyronitrile-initiated polymerization of various N-substituted diallylammonium, N-ethyldimethallylammonium, and triallylammonium chlorides yielded as the respective major by-products 2-substituted 6, 6-dimethylperhydro-5-isoindolones, 2-ethyl-3a, 6,6,7a-tetramethylperhydro-5-isoindolone, and 2-allyl-6,6-dimethylperhydro-5-isoindolone. These isoindolones are formed from pyrrolidylmethylene radical precursors and indicate that, in agreement with recent ESR studies, radical addition to diallylamines results in the formation of pyrrolidine derivatives and not piperidines as previously supposed. The reactions of azobisisobutyronitrile and azobisis-obutyramidine dihydrochloride with the models, N,N-dimethylallylammonium and N,N,2-trimethylallylammonium chlorides, are also described.