Protecting-Group-Free Iterative Exponential Growth Method for Synthesizing Sequence-Defined Polymers
Protecting-Group-Free Iterative Exponential Growth Method for Synthesizing Sequence-Defined Polymers
复制标题
用于合成序列定义聚合物的无保护基迭代指数增长方法
DOI：
10.1021/acsmacrolett.0c00812
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发表时间：
2021-01-19
影响因子：
7.015
通讯作者：
Zhang, Ke
中科院分区：
文献类型：
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作者：
Li, Zi;Ren, Xiangzhu;Zhang, Ke
作为合成单分散序列限定聚合物的主要策略，已知的迭代指数增长（IEG）方法都是基于保护基化学发展起来的，其中额外的脱保护反应增加了它们的合成步骤，降低了它们的原子经济性。在这项研究中，我们开发了一种无保护基团的IEG方法，通过结合三个正交点击反应的铜（I）催化的叠氮-炔环加成（CuAAC），硫-氟交换反应（SuFEx），和Ugi四组分反应（Ugi-4CR）形成的序列定义的聚合物。在这种方法中，低聚物合成从三个单体之间的三个平行CuAAC、SuFEx和Ugi-4CR偶联开始，每个单体具有两个正交的可点击末端基团。通过迭代地应用平行的CuAAC、SuFEx和Ugi-4CR来偶联三种所得的寡聚物，每种寡聚物具有两个正交的可点击末端，这种方法可以以高效率同时指数地生长三种不同的序列限定的聚合物，而不需要保护基团化学。此外，每个Ugi-4CR偶联反应可以引入两个外部侧基，以提供所得序列限定的聚合物的分子变化和侧链官能化。
As a main synthetic strategy for monodisperse sequence-defined polymers, the known iterative exponential growth (IEG) methods were all developed on protecting-group chemistry, where the additional deprotection reactions increased their synthetic steps and decreased their atom economy. In this study, we developed a protecting-group-free IEG method for the formation of sequence-defined polymers by combining three orthogonal click reactions of copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC), sulfur-fluoride exchange reaction (SuFEx), and Ugi four-component reaction (Ugi-4CR). In this approach, oligomer synthesis began with three parallel CuAAC, SuFEx, and Ugi-4CR couplings among three monomers each with two orthogonal clickable end groups. By iteratively applying parallel CuAAC, SuFEx, and Ugi-4CR to couple three resultant oligomers, each having two orthogonal clickable terminals, this approach could exponentially grow three different sequence-defined polymers simultaneously with high efficiency, requiring no protecting-group chemistry. Additionally, each Ugi-4CR coupling reaction could introduce two external side groups to provide the molecular variation and side-chain functionalization for the resultant sequence-defined polymers.