北京大学王剑波团队报道了钯催化活性/可控环丙烯的乙烯基加成聚合。相关研究成果发表在2021年10月14日出版的国际知名学术期刊《美国化学会杂志》。

尽管环丙烯（CPE）在有机合成和开环复分解聚合（ROMP）中有各种用途，但其乙烯基加成聚合仍有零星的探索，相应的活性/可控聚合仍然是一个巨大的挑战。主要障碍是中间体的固有不稳定性和传播的动力学障碍。

该文展示了由硫酰胺双膦配体连接的[Pd（π-烯丙基）Cl]2催化的3-甲基-3-羧甲基CPE的活性/可控乙烯基加成聚合。聚合过程中，平均分子量（Mn）与转化率的呈线性关系，分子量分散度（Mw/Mn）较小。Mn值随单体与催化剂初始投料比的增加呈线性增加。此外，通过顺序单体加成的控制嵌段共聚是成功的。所有这些都证实了这种聚合的活性。催化剂配体和环丙烯部分的侧羰基的协同协同作用在以活性/可控方式实现有效聚合中起着关键作用。

附：英文原文

Title: Palladium-Catalyzed Living/Controlled Vinyl Addition Polymerization of Cyclopropenes

Author: Zepeng Zhang, Yunpeng Gao, Shufeng Chen, Jianbo Wang

Issue&Volume: October 14, 2021

Abstract: Despite the various utilities of cyclopropenes (CPEs) in organic synthesis and ring-opening metathesis polymerization (ROMP), their vinyl addition polymerization has been sporadically explored, and the corresponding living/controlled polymerization remains a formidable challenge. The major obstacle is the intrinsic instability of the intermediate and the kinetic barrier for propagation. Herein a living/controlled vinyl addition polymerization of 3-methyl-3-carboxymethyl CPEs, catalyzed by [Pd(π-allyl)Cl]2 ligated by a sulfinamide bisphosphine ligand, is demonstrated. A plot of the number-average molecular weight (Mn) versus the conversion was found to be linear during the polymerization, with the molecular weight dispersity (Mw/Mn) remaining narrow. The Mn values increased linearly with the increase in the initial feed ratio of monomer to catalyst. Furthermore, controlled block copolymerization via sequential monomer addition was successful. All of these points corroborate the living nature of this polymerization. The synergistic coordination action of the catalyst ligand and the lateral carbonyl group in the cyclopropene moiety plays a key role in achieving the efficient polymerization in a living/controlled manner.

DOI: 10.1021/jacs.1c09071

Source: https://pubs.acs.org/doi/10.1021/jacs.1c09071