Rapid Metal -free Macromolecular Coupling via in situ Nitrile Oxide-Activated Alkene Cycloaddition.
Rapid Metal -free Macromolecular Coupling via in situ Nitrile Oxide-Activated Alkene Cycloaddition.
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DOI：
10.1002/pola.27371
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发表时间：
2014-11-01
期刊：
影响因子：
--
通讯作者：
Theogarajan LS
中科院分区：
文献类型：
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作者：
Isaacman MJ;Cui W;Theogarajan LS
腈氧化物1，3偶极环加成反应是一种简单而有效的偶联方法。然而，腈氧化物的自二聚化阻止了这种策略在大分子偶联中的广泛应用。通过结合原位腈氧化物生成与高活性活化亲偶极试剂，我们已经克服了这些障碍，并提出了一种无金属的大分子偶联策略，用于几种阿坝三嵌段共聚物的模块化合成。以氯肟封端的聚二甲基硅氧烷B-嵌段原位生成腈氧化物，并与几种不同的亲水性（聚（2-甲基恶唑啉）和聚（乙二醇））和聚（N-异丙基丙烯酰胺）或疏水性（聚（L-丙交酯））A-嵌段以快速方式以高产率在活化的偶极亲电体中封端。这种方法克服了以前报道的无金属方法的许多缺点，由于其快速的动力学，多功能性，可扩展性和易于引入必要的功能。腈氧化物环加成反应是合成生物相容性聚合物纳米结构的一种有吸引力的大分子偶联策略。无金属聚合物-聚合物共轭对智能材料的发展至关重要，特别是用于药物递送和生物传感。我们在这里提出了一个可扩展的，通用的和模块化的程序阿坝三嵌段共聚物的合成的基础上1，3偶极环加成。我们展示了该方法的多功能性，通过耦合亲水性和疏水性的A-嵌段与聚硅氧烷B-嵌段。亲水性A块赋予隐形，温敏和自组装纳米图案化行为成功地耦合，说明模块化的方法。
Nitrile oxide 1,3 dipolar cycloaddition is a simple and powerful coupling methodology. However, the self-dimerization of nitrile oxides has prevented the widespread use of this strategy for macromolecular coupling. By combining an in situ nitrile oxide generation with a highly reactive activated dipolarophile, we have overcome these obstacles and present a metal-free macromolecular coupling strategy for the modular synthesis of several ABA triblock copolymers. Nitrile oxides were generated in situ from chloroxime terminated poly(dimethylsiloxane) B-blocks and coupled with several distinct hydrophilic (poly(2-methyloxazoline) and poly(ethylene glycol)), and poly(N-isopropylacrylamide) or hydrophobic (poly(L-lactide) A-blocks terminated in activated dipolarophiles in a rapid fashion with high yield. This methodology overcomes many drawbacks of previously reported metal-free methods due to its rapid kinetics, versatility, scalability, and ease of introduction of necessary functionality. Nitrile oxide cycloaddition should find use as an attractive macromolecular coupling strategy for the synthesis of biocompatible polymeric nanostructures. Metal-free polymer-polymer conjugation is crucial to the development of smart materials, especially for drug delivery and biosensing. We present here a scalable, versatile and modular procedure for the synthesis of ABA triblock copolymers based on 1,3 dipolar cycloaddition. We show the versatility of the approach by coupling both hydrophilic and hydrophobic A-blocks with a polysiloxane B-block. Hydrophilic A blocks imparting stealth, thermoresponsive and self-assembled nanopatterning behavior were successfully coupled illustrating the modularity of the approach.