中国科学院化学所张科团队报道了基于开环/闭环级联反应的大环单体控制开环聚合方法。相关研究成果发表在2023年11月6日出版的《美国化学会杂志》。

在聚合物化学中，开发从大环单体合成具有明确结构的骨架官能化，和序列控制聚合物的可控开环聚合（ROP）方法是非常理想的。

该文中，研究人员开发了一种新的大环通用控制ROP方法，用于生产具有可控分子量和窄分散性（<1.1）的骨架功能和序列控制的聚氨酯和聚酰胺。该方法的关键是引入三甲基锁单元，一种有效的基于环化的自不动间隔体，作为“开环触发器”进入大环单体环。ROP是由伯胺亲核试剂对环活化的碳酸酯/酯基团的攻击引发的，并导致大环单体开环。

随后，三甲基锁单元自发6-exo-trig环化发生，分离该开环触发器并再生伯胺端基。再生的伯胺基团然后可以用于通过迭代开环-闭环级联反应来传播聚合物链。多功能ROP方法可用于合成水溶性聚氨酯、骨架可降解聚氨酯和聚（酯酰胺），以及具有明确大分子结构的序列控制聚（氨基酸）。

附：英文原文

Title: Controlled Ring-Opening Polymerization of Macrocyclic Monomers Based on Ring-Opening/Ring-Closing Cascade Reaction

Author: Wensen Chen, Changjuan Guo, Hao Ding, Xingyu Yang, Ke Zhang

Issue&Volume: November 6, 2023

Abstract: The development of a controlled ring-opening polymerization (ROP) method for synthesizing backbone-functionalized and sequence-controlled polymers with well-defined architectures from macrocyclic monomers is highly desirable in polymer chemistry. Herein, we developed a novel general controlled ROP of macrocycles for producing backbone functional and sequence-controlled polyurethanes and polyamides with controlled molecular weights and narrow dispersities ( < 1.1). The key to this method is the introduction of a trimethyl lock unit, an efficient cyclization-based self-immolative spacer, into the macrocyclic monomer ring as a “ring-opening trigger.” ROP is initiated by the attack of a primary amine nucleophile on the ring-activated carbonate/ester group, leading to the ring opening of the macrocyclic monomer. Subsequently, spontaneous 6-exo-trig cyclization of the trimethyl lock unit occurs, detaching this ring-opening trigger and regenerating the primary amine end group. The regenerated primary amine group can then be used to propagate the polymer chain by iterating the ring-opening-ring-closing cascade reaction. The versatile ROP method can be applied in the synthesis of water-soluble polyurethanes, backbone-degradable polyurethanes and poly(ester amide)s, and sequence-controlled poly(amino acid)s with well-defined macromolecular architectures.

DOI: 10.1021/jacs.3c10765

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.3c10765