Cationic polyelectrolytes were obtained from anionic synthesis of poly[5-(N,N-dialkylamino)isoprene]s by quaternization of the tertiary amino group. The reaction takes place easily using dimethyl sulfate as alkylating agent. The quaternized polymers are completely water-soluble and were characterized by NMR spectroscopy. An application of this material as phase transfer catalyst in the polymerization of 4-bromo-2,6-dimethyl phenol was also demonstrated.