Helically chiral polyisocyanates and polyquinoxalines as organocatalysts

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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.