Kato Ryusei, Kanazawa Arihiro, Aoshima Sadahito
Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
ACS Macro Lett. 2019 Nov 19;8(11):1498-1503. doi: 10.1021/acsmacrolett.9b00745. Epub 2019 Oct 25.
Silylacetal was demonstrated to function as a promising cleavable moiety for preparing polymers degradable via desilylation under diverse, mild conditions. The silylacetal moieties were installed in the main chain of the polymers via the controlled cationic copolymerization of trimethylsilyl vinyl ether (TMSVE) and a cyclic acetal under appropriately designed conditions. Importantly, desilylation reactions of the silylacetal units occurred under weak acid, base, or fluoride ion conditions, which triggered the degradation of the polymer via the spontaneous cleavage of the unstable hemiacetal moieties generated by the desilylation. Moreover, silylacetal moieties were successfully incorporated at the desired positions in the main chain via the addition of a small portion of TMSVE during the controlled cationic copolymerization of a vinyl ether and cyclic acetal. The strategy devised in this study will allow the design of elaborate polymers that undergo degradation triggered by various stimuli.
硅基缩醛被证明是一种很有前景的可裂解部分，用于制备在各种温和条件下可通过脱硅作用降解的聚合物。通过在适当设计的条件下，使三甲基硅基乙烯基醚（TMSVE）与环状缩醛进行受控阳离子共聚反应，将硅基缩醛部分引入聚合物的主链中。重要的是，硅基缩醛单元的脱硅反应在弱酸、弱碱或氟离子条件下发生，这通过脱硅作用产生的不稳定半缩醛部分的自发裂解引发聚合物的降解。此外，在乙烯基醚和环状缩醛的受控阳离子共聚过程中，通过添加一小部分TMSVE，硅基缩醛部分成功地引入到主链中的所需位置。本研究中设计的策略将允许设计出由各种刺激引发降解的精细聚合物。
