Semenov Sergey N, Belding Lee, Cafferty Brian J, Mousavi Maral P S, Finogenova Anastasiia M, Cruz Ricardo S, Skorb Ekaterina V, Whitesides George M
Department of Chemistry and Chemical Biology , Harvard University , 12 Oxford Street , Cambridge , Massachusetts 02138 , United States.
Kavli Institute for Bionano Inspired Science and Technology, School of Engineering and Applied Sciences , Harvard University , 29 Oxford Street , Cambridge , Massachusetts 02138 , United States.
J Am Chem Soc. 2018 Aug 15;140(32):10221-10232. doi: 10.1021/jacs.8b05048. Epub 2018 Aug 7.
This work describes the autocatalytic copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction between tripropargylamine and 2-azidoethanol in the presence of Cu(II) salts. The product of this reaction, tris-(hydroxyethyltriazolylmethyl)amine (N(CN)), accelerates the cycloaddition reaction (and thus its own production) by two mechanisms: (i) by coordinating Cu(II) and promoting its reduction to Cu(I) and (ii) by enhancing the catalytic reactivity of Cu(I) in the cycloaddition step. Because of the cooperation of these two processes, a rate enhancement of >400× is observed over the course of the reaction. The kinetic profile of the autocatalysis can be controlled by using different azides and alkynes or ligands (e.g., ammonia) for Cu(II). When carried out in a layer of 1% agarose gel, and initiated by ascorbic acid, this autocatalytic reaction generates an autocatalytic front. This system is prototypical of autocatalytic reactions where the formation of a product, which acts as a ligand for a catalytic metal ion, enhances the production and activity of the catalyst.
本研究描述了在铜（II）盐存在下，三丙炔胺与2-叠氮乙醇之间的自催化铜催化叠氮化物-炔烃环加成（CuAAC）反应。该反应的产物三（羟乙基三唑基甲基）胺（N(CN)）通过两种机制加速环加成反应（从而促进自身生成）：（i）通过配位铜（II）并促进其还原为铜（I）；（ii）通过增强铜（I）在环加成步骤中的催化活性。由于这两个过程的协同作用，在反应过程中观察到反应速率提高了400倍以上。自催化的动力学过程可以通过使用不同的叠氮化物、炔烃或铜（II）的配体（如氨）来控制。当在1%琼脂糖凝胶层中进行，并由抗坏血酸引发时，这种自催化反应会产生一个自催化前沿。该体系是自催化反应的典型例子，即产物作为催化金属离子的配体，其形成会增强催化剂的生成和活性。
