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 C-13 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.

Automated summary

This study investigated the copolymerization of diene comonomers bearing boronic acid masked with 1,8-diaminonaphthalene (dan) with isoprene or butadiene, using a neodymium borohydride complex as a catalyst. The comonomers showed tolerance to excess modified methylaluminoxane (MMAO) and were applicable to a polymerization system using MMAO. However, the corresponding pinacol borate was highly reactive towards MMAO and did not incorporate into the obtained polymer. C-13 NMR analysis revealed that all the comonomers were located at the chain end of the hydrogenated copolymer. Further functionalization using the boron moiety at the polymer chain end was also investigated.