Houck Hannes A, De Bruycker Kevin, Billiet Stijn, Dhanis Bastiaan, Goossens Hannelore, Catak Saron, Van Speybroeck Veronique, Winne Johan M, Du Prez Filip E
Department of Organic and Macromolecular Chemistry , Polymer Chemistry Research Group and Laboratory for Organic Synthesis , Ghent University , Krijgslaan 281 S4-bis , 9000 Ghent , Belgium . Email:
Preparative Macromolecular Chemistry , Institut für Technische Chemie und Polymerchemie , Karlsruhe Institute of Technology (KIT) , Engesserstraße 18 , 76131 Karlsruhe , Germany.
Chem Sci. 2017 Apr 1;8(4):3098-3108. doi: 10.1039/c7sc00119c. Epub 2017 Feb 16.
The reaction of triazolinediones (TADs) and indoles is of particular interest for polymer chemistry applications, as it is a very fast and irreversible additive-free process at room temperature, but can be turned into a dynamic covalent bond forming process at elevated temperatures, giving a reliable bond exchange or 'transclick' reaction. In this paper, we report an in-depth study aimed at controlling the TAD-indole reversible click reactions through rational design of modified indole reaction partners. This has resulted in the identification of a novel class of easily accessible indole derivatives that give dynamic TAD-adduct formation at significantly lower temperatures. We further demonstrate that these new substrates can be used to design a directed cascade of click reactions of a functionalized TAD moiety from an initial indole reaction partner to a second indole, and finally to an irreversible reaction partner. This controlled sequence of click and transclick reactions of a single TAD reagent between three different substrates has been demonstrated both on small molecule and macromolecular level, and the factors that control the reversibility profiles have been rationalized and guided by mechanistic considerations supported by theoretical calculations.
三唑啉二酮（TADs）与吲哚的反应在聚合物化学应用中特别受关注，因为它在室温下是一个非常快速且不可逆的无添加剂过程，但在升高温度时可转变为动态共价键形成过程，产生可靠的键交换或“反点击”反应。在本文中，我们报告了一项深入研究，旨在通过合理设计修饰的吲哚反应伙伴来控制TAD - 吲哚可逆点击反应。这导致鉴定出一类新型的易于获得的吲哚衍生物，它们在显著更低的温度下形成动态TAD - 加合物。我们进一步证明，这些新底物可用于设计从初始吲哚反应伙伴到第二个吲哚，最终到不可逆反应伙伴的功能化TAD部分的定向点击反应级联。单一TAD试剂在三种不同底物之间的这种可控的点击和反点击反应序列已在小分子和大分子水平上得到证明，并且控制可逆性概况的因素已通过理论计算支持的机理考虑进行了合理化和指导。
