Conventionally inaccessible end-functionalized vinyl polymers were synthesized via orthogonal side-chain replacement for terminal and repeating units of poly(alkenyl boronate)s. A terminal-defined polymer of isopropenyl boronic acid pinacol ester (IPBpin) was synthesized via RAFT polymerization, and subsequent cobalt (Co)-catalyzed end olefination afforded the polymer carrying the C(sp²)–B bond at the terminal and the C(sp³)–B bond in repeating units. Herein, the terminal C(sp²)–B bond was selectively transformable via palladium (Pd)-catalyzed Suzuki-Miyaura cross coupling, and subsequent transformation of the repeating C(sp³)–B unit gave the poly(α-methyl vinyl alcohol) [poly(MVA)] bearing various functional groups at the terminal. The boron-based stepwise polymer reaction thus overcame the synthetic difficulty of the end-functionalized poly(MVA), which is ascribed to the poor polymerization ability of the corresponding acetate monomer, i.e., isopropenyl acetate.

中文翻译：

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正交 C-B 键转换作为一种多功能合成末端功能化聚合物的方法

传统上难以接近的末端官能化乙烯基聚合物是通过正交侧链置换来合成聚（硼酸烯基酯）的末端和重复单元。通过 RAFT 聚合合成了异丙烯基硼酸频哪醇酯 (IPBpin) 的末端定义聚合物，随后钴 (Co) 催化末端烯化得到末端带有 C(sp ² )-B 键和 C( sp ³ )-B 键在重复单元中。在此，末端 C(sp ² )-B 键可通过钯 (Pd) 催化的 Suzuki-Miyaura 交叉偶联选择性转化，随后重复的 C(sp ³)–B 单元产生在末端带有各种官能团的聚 (α-甲基乙烯醇) [聚 (MVA)]。因此，硼基逐步聚合物反应克服了末端官能化聚（MVA）的合成困难，这是由于相应的乙酸酯单体（即乙酸异丙烯酯）的聚合能力差。