Chirality directed self-assembly: in situ construction of recyclable and reusable Janus dendrimers

Abstract

The underlying theme at the forefront of synthetic organic chemistry has always been about compounding simple precursors into more complex molecular targets. However, this strenuous process often involves the generation of toxic and hazardous waste. In order to move towards a more sustainable chemistry, optimization of the use of catalysts for better efficiency is essential. To that end, the ideal strategy should be focused on running a series of catalyzed reactions in a single vessel. This is advantageous in its practicality and would significantly reduce labor, time, and waste production. There are a few existing strategies that are in existence to further the single-pot synthesis goal. However, there are still many limitations on catalyst incompatibilities and fine-tuning microenvironments of immobilized catalysts. To that end, our overall goal was to provide a strategy to overcome some of these limitations. Due to time constraints, the scope of this thesis was focused on a proof of concept strategy involving only dendrimers without catalysts. Nonetheless, the novel methodology presented here could one day be extended to solve the proposed issues. Although many different strategies to build dendrimers have already been demonstrated, most of these dendrimers are created with uniform functional groups and require long reaction times with tedious purification processes. Herein, we successfully demonstrate a novel metal-ligand self-assembly approach with a high level of chiral discrimination to construct Janus dendrimers in situ. As far as we are aware, this is the first such example utilizing metal-ligand interaction for the construction of Janus dendrimers. Using this approach we were able to generate a large library as well as recyle and reuse each dendritic subunit.