利用非手性单体制备手性螺旋聚异腈及应用于动力学拆分

Due to its stable helical structure, polyisocyanide has a wide range of applications in many fields. Functional helical polyisocyanide can be synthesized through introducing groups for kinetic resolution to the pendants. In this project, a class of achiral isocyanide monomers containing kinetic resolution groups such as thiourea, pyridine and acyl donors have been designed. Then, by using chiral ligand, chiral solvent, chiral additive or chiral macroinitiator during polymerization process, linear and core-shell star optically active helical polyisocyanides with kinetic resolution sites as pendants will be prepared. These optically active polyisocyanides will be employed for kinetic resolution of racemic alcohols or amines. The effects of the helical structure as well as different substituents of pendants on separation factor and resolution performance will be studied. Meanwhile, the relationship between the helical structure and the kinetic resolution properties of the polymers will be investigated. What’s more, the recovery and reusing of optically active helical polymers will be studied. The success of this project will not only develop a new method for synthesizing functional polyisocyanides but also provide novel chiral polymer materials for kinetic resolution.

聚异腈具有稳定的螺旋结构及广泛的应用前景，若在螺旋聚异腈侧基引入有动力学拆分位点的基团则能赋予螺旋聚异腈动力学拆分的功能。本项目拟将硫脲、吡啶及酰基供体等具有动力学拆分位点的基团引入非手性异腈单体，通过聚合过程使用手性配体、手性溶剂、手性添加剂或手性大分子引发剂诱导非手性异腈单体进行螺旋选择性聚合，结合后修饰的方法制备线型和核壳多臂星型螺旋聚异腈。利用聚异腈螺旋手性和侧基动力学拆分位点的协同作用实现对外消旋醇或胺类化合物的动力学拆分，探索动力学拆分过程中聚异腈螺旋结构的手性调控作用，系统研究光学活性螺旋链结构、动力学拆分位点上不同取代基对分离因子及拆分性能的影响，揭示聚合物螺旋结构与动力学拆分性能之间的内在联系，研究手性螺旋聚异腈的回收及循环使用。本项目的研究工作将为功能化螺旋聚异腈的合成提供新的方法，为动力学拆分领域提供新型高效的手性拆分材料。

受自然界螺旋结构的启发，人工合成螺旋结构可控的高分子材料备受关注。因手性单体的来源有限、合成较难等不足，使得通过手性单体不对称聚合获得手性高分子材料的方法有一定的局限，因此采用少量手性催化剂引发非手性单体螺旋选择性聚合获得大量手性材料的策略具有重大意义。本项目发展了手性Pd(II)/Wei-phos催化体系，该体系能够高效引发非手性异腈单体活性聚合，并且可通过简便分离获得不同数均分子量的单一右手和单一左手螺旋聚合物，提出并验证了聚合过程中的自终止现象。同时又发展了一种新型手性Ni(II)/Xiao-phos催化体系，该体系能够高效引发非手性联烯单体活性聚合，且聚合过程具有较高的区域选择性和螺旋选择性，得到高选择性的螺旋2,3-聚联烯，所得的手性螺旋聚异腈及聚联烯的形貌均用原子力显微镜进行了表征，可清晰分辨出聚合物主链的螺旋结构。本项目的研究工作不仅为功能化螺旋高分子材料的合成提供新的方法，还为研究手性传递及手性放大提供了理论基础。