Synthesis of Optically Active Helical Polycarbenes through Helix-Sense-Selective Polymerization Strategy and Their Application in Chiral Separation
Synthesis of Optically Active Helical Polycarbenes through Helix-Sense-Selective Polymerization Strategy and Their Application in Chiral Separation
复制标题
通过螺旋选择性聚合策略合成光学活性螺旋聚碳烯及其在手性分离中的应用。
DOI：
10.1021/acsmacrolett.2c00212
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发表时间：
2022-06-21
影响因子：
7.015
通讯作者：
Wu, Zong-Quan
中科院分区：
文献类型：
--
作者：
Gao, Bao-Rui;Wu, Yong-Jie;Wu, Zong-Quan
本文设计并合成了具有旋光性的螺旋聚卡宾，通过含手性膦配体的π-烯丙基PdCl催化重氮乙酸酯单体与二甲基苄基酯侧基在室温下进行螺旋选择性聚合（HSSP），得到了具有旋光性的螺旋聚卡宾。聚合反应以活性可控的方式进行，得到了一系列具有所需数均分子量和窄分子量分布的螺旋聚卡宾。圆二色谱和紫外-可见光谱分析表明，这些聚卡宾具有稳定的螺旋构象，且螺旋方向与手性膦配体的手性有关。进一步的研究表明，所得聚卡宾在溶液中的螺旋构象是来自聚合物主链，而不是分子间的聚集。此外，所制备的，光学活性，螺旋聚卡宾具有良好的对映选择性结晶苏氨酸外消旋体的能力。对映体过量（e.e.）用所制备的螺旋聚卡宾作为手性分离剂，诱导结晶率可达83%。
In this work, helical polycarbenes with optical activity were designed and facilely synthesized through the helix-sense-selective polymerization (HSSP) of the diazoacetate monomer with a dimethylbenzyl ester pendant catalyzed by pi-allylPdCl with chiral phosphine ligands at room temperature. The polymerization was carried out in a living and controlled style, and a range of helical polycarbenes with the desired number-average molecular weights and narrow molecular weight distributions were obtained. Circular dichroism and UV-vis analyses revealed that these polycarbenes exhibited a stable helical conformation with a preferred handedness, and their helical directions were dependent on the chirality of the chiral phosphine ligands. Further studies showed that the helical conformation of the obtained polycarbenes was from the polymeric backbone rather than the intermolecular aggregation in the solutions. Moreover, the prepared, optically active, helical polycarbenes possessed excellent enantioselective crystallization ability for threonine racemates. The enantiomeric excess (e.e.) of the induced crystals could be up to 83% via utilizing the prepared helical polycarbenes as a chiral separation agent.