Chiral N-Heterocyclic Carbenes as Organocatalysts and Ligands for Metal-Mediated Asymmetric Processes

不对称金属介导的过程在有机合成中是至关重要的。多年来，手性膦一直是手性金属络合物不对称性的来源。然而，近些年来，N-杂环卡宾(NHCs)已经开始作为配体在许多金属介导的过程中扮演着重要的角色，在某种程度上，它们现在已经在这一角色上与膦竞争，甚至超过了膦。然而，在更专业的不对称催化领域，NHCS仍然落后于膦。本文介绍了新型手性NHC金属络合物的制备及其在不对称合成中的应用，特别是在不对称烯烃歧化反应中的应用。同样重要的是要认识到，NHC也可以与主族金属和非金属形成络合物，然后络合物也可能在合成中有用。这一领域到目前为止还没有被探索过，本研究项目将研究NHC主族配合物在有机合成中的潜力。此外，自由的NHC本身表现出的性质使手性NHC具有亲核有机催化剂的吸引力。最后，建议研究完全新颖的类卡宾物种的制备和反应，这些物种可能以类似卡宾的方式作为配体。

Asymmetric metal-mediated processes are vital in organic synthesis. For many years, chiral phosphines have provided the source of asymmetry in chiral metal complexes. In recent years, however, N-heterocyclic carbenes (NHCs) have begun to play a prominent role as ligands in many metal-mediated processes, to the extent that they now rival, and surpass, phosphines in this role. However, in the more specialised field of asymmetric catalysis, NHCs still lag beh phosphines. The research described herein is directed towards the preparation of new chiral NHC metal complexe their application in asymmetric synthesis, and in particular in asymmetric alkene metathesis processes. It is also important to recognise that NHCs may also form complexes with main group metals and non-metals, and that then complexes may also be useful in synthesis. This area is so far unexplored, and this research project will investigate the potential of NHC main group complexes in organic synthesis. Additionally, the free NHCs themselves display properties that make the chiral NHCs attractive candidates for nucelophilic organocatalysts. Finally, it is proposed to investigate preparation and reactions of completely novel, carbene-like species, which may act as ligands in a similar manner carbenes.