dimerizations of α-methylstyrene (αMS) derivatives via β-C−H scission were subsequently used for sulfur-free cationic RAFT polymerization of αMS and isobutylene (IB) via β-C−C scission. Telechelic polymers and block copolymers of αMS and methyl methacrylate were also prepared from bifunctional exo-olefins and mechanistic transformations from cationic to radical RAFT polymerization, respectively,