Helically chiral polyisocyanates and polyquinoxalines as organocatalysts

我们的工作目标是开发和应用螺旋手性聚合物作为有机催化剂。与此同时，与低分子量体系相比，聚合物不仅应该提供与工艺相关的优势，而且应该是功能的载体。为了达到这个目的，有机催化活性单元以这样一种方式并入单体中，聚合后，它们的微环境变得均匀，并受到聚合物主链手性的影响。因此，聚合物的构型稳定性和从主链到催化活性位点的有效手性转移是主要的兴趣。基于这些核心需求，我们决定使用多异氰酸酯、多喹啉类以及作为一种新型聚合物的多胍类。利用这些聚合物，我们打算通过横向联芳基单元中主链介导的不对称手性诱导来解决手性转移问题。在多胍的情况下，螺旋手性主链本身可以作为催化活性位点。由此，在依赖于轴向手性br ønstedt酸/碱或轴向手性亲核试剂的有机催化中展开了应用。此外，多胍类化合物还可作为极性相反的“ACDC”催化剂。

The goal of our work is to develop and to apply helically chiral polymers as organocatalysts. At the same time the polymer should not only offer process-related advantages if compared to low molecular weight systems, but it should be a carrier of function. Towards this end organocatalytically active units were incorporated into monomers in such a way that, after polymerisation, their microenvironments get uniform and influenced by the chirality of the polymer backbone. Therefore, the configurational stability of the polymer and an efficient chirality transfer from the backbone to the catalytically active sites is of prime interest. Based on these central demands we decided to use polyisocyanates, polyquinoxalines and, as a new class of polymers, polyguanidines. With these polymers we intend to solve the problem of chirality transfer by backbone mediated asymmetric induction of chiral axes in lateral biaryl units. In case of the polyguanidines the helically chiral backbone itself may serve as a catalytically active site. From that, applications in organocatalysis unfold which rely on axially chiral Brønstedt-acids/bases or axially chiral nucleophiles. Moreover, the poyguanidines may be used as "ACDC"-catalysts with reversed polarity.