Controlled cationic polymerization of p-(chloromethyl)styrene: BF3-catalyzed selective activation of a C-O terminal from alcohol

Controlled cationic polymerization of p-(chloromethyl)styrene (CMS) was achieved with an alcohol [CH3CH(Ph)OH] as an initiator and a highly oxophilic Lewis acid, BF3·OEt2, as an activator/catalyst. The polymerization is initiated by the BF3-mediated selective activation of the C−O bond of the alcohol and proceeds via a similar activation of the resulting ∼∼C−OH dormant polymer terminal to give linear polymers without branched structures that would form via reactions of the chloromethyl pendent groups. Addition of a small amount of water retarded the polymerization to give controlled molecular weights that increased with conversion and were close to the calculated values for living polymers. Additional use of tetrabutylammonium hydroxide (n-Bu4NOH) as a hydroxide anion source further narrowed the molecular weight distribution (Mw/Mn = 1.5−1.8). Copolymerization of CMS and styrene or p-chlorostyrene with the BF3-based system also gave copolymers with controlled molecular weights. This is the first example o...