Synthesis of Chain-End Functional Polydienes Using Diene Comonomer Bearing Boronic Acid Masked with Diaminonaphthalene.

Diene comonomers bearing boronic acid masked with 1,8-diaminonaphthalene (dan) were applied to copolymerization with isoprene or butadiene using neodymium borohydride complex as a catalyst. The comonomers were tolerant to excess modified methylaluminoxane (MMAO) and thus were applicable to the polymerization system using MMAO. On the other hand, the corresponding pinacol borate was highly reactive toward MMAO, and no incorporation into the obtained polymer was observed. A 13C NMR microstructural analysis of the hydrogenated copolymer revealed that all of the comonomers were located at the chain end. Further functionalization using the boron moiety at the polymer chain end was also investigated.