Cornell University , Ithaca , New York 14853 , United States.
J Am Chem Soc. 2019 Jul 10;141(27):10605-10609. doi: 10.1021/jacs.9b04961. Epub 2019 Jul 1.
Cationic polymerizations provide a valuable strategy for preparing macromolecules with excellent control but are inherently sensitive to impurities and commonly require rigorous reagent purification, low temperatures, and strictly anhydrous reaction conditions. By using pentacarbomethoxycyclopentadiene (PCCP) as the single-component initiating organic acid, we found that a diverse library of vinyl ethers can be controllably polymerized under ambient conditions. Additionally, excellent chain-end fidelity is maintained even without rigorous monomer purification. We hypothesize that a tight ion complex between the PCCP anion and the oxocarbenium ion chain end prevents chain-transfer events and enables a polymerization with living characteristics. Furthermore, terminating the polymerization with functional nucleophiles allows for chain-end functionalization in high yields.
阳离子聚合提供了一种制备具有优异控制能力的聚合物的有价值策略，但对杂质非常敏感，通常需要严格的试剂纯化、低温和严格的无水反应条件。通过使用五羧酸酯环戊二烯（PCCP）作为单一成分引发有机酸，我们发现可以在环境条件下可控聚合各种乙烯基醚。此外，即使没有严格的单体纯化，也能保持良好的链端保真度。我们假设 PCCP 阴离子和氧杂碳鎓离子链末端之间的紧密离子配合物可以防止链转移反应，并使聚合具有活性特征。此外，用功能亲核试剂终止聚合可以高产率地进行链端官能化。
