Cation radical chain cycloaddition polymerization and cationic macrocyclopolymerization

Strategies for accelerating cation radical chain polymerization are propose d and implemented. In one approach, unsymmetrical monomers are prepared whi ch have a propenyl group to provide facile ionization by the aminium salt i nitiator and a vinyl group to provide diminished steric effects resulting i n an acceleration of the cycloaddition step in the propagation cycle. This strategy results in dramatic increases in cation radical chain polymerizati on rates, but cationic cyclopolymerization generating 15-membered rings (ma crocyclopolymerization) is competitive because of the ease of electrophilic attack on the electron rich, unhindered, vinyl moiety. A successful strate gy for accelerating cation radical cycloaddition polymerization selectively is then proposed and demonstrated. (C) 2000 Society of Chemical Industry.