Atropoisomerism of nitrogen-based ligands and natural products
thesisposted on 15.01.2020 by Claire M. Gillings
In order to distinguish essays and pre-prints from academic theses, we have a separate category. These are often much longer text based documents than a paper.
This thesis details the attempt to design and synthesis a range of ligands and organocatalysts based on a common backbone design. Initial results were promising with a number of ligands being generated from our common C2-symmetric backbone. Unfortunately none of the molecules synthesises gave promising results in test reactions. Variations on the initial design also failed to give any encouraging results. More positively, work on phosphorus-nitrogen (P,N) ligands was successful, with a number of different ligands being synthesised and metal complexes prepared. Pleasingly we were able to obtain X-ray crystallography of one of these complexes indicating that the ligand was complexed to the metal via the phosphorus moiety. Work using the Buchwald-Hartwig reaction for coupling aryl bromides to both 1,2,3,4-tetrahydroisoquinoline and 1,2,3,4-tetrahydroquinoline was successful, with methodology being developed which we believe can be applied to the synthesis of Ancistrocladinium A. In particular the coupling between 1,2,3,4-tetrahydroisoquinoline and 1-bromonaphthalene afforded us the full carbon skeleton of the ring system of the natural product in one step, from which we were able to generate the iminium salt. We also investigated an alternative route for the synthesis of Ancistrocladinium A achieving atropoisomerism. Experimental data is provided in chapter three, and all X-ray crystallography structures reported in chapter two are provided in the appendix.