HYDROAMINATION OF ALKENES AND ALKYNES WITH GROUP 2-CENTRED CATALYSTS

对世界资源日益增长的需求要求化学家们设计出更有创造性的方法来开发现有的和新的化学原料。所谓的可持续化学（也被称为“绿色化学”）的后果影响到制造过程的所有阶段。这包括通过工程、催化和合成化学的进步来提高反应的效率。原子效率或原子经济概念是一种非常有用的工具，可用于快速评估由特定产品的替代路线产生的废物量。它的计算方法是用所需产物的分子量除以相关反应的化学计量方程中产生的所有物质的分子量总和。本提案旨在开发环境友好的催化剂，用于100%原子效率地将氨基烯烃和-炔转化为有价值的杂环化合物。虽然这种转化在一系列镧系催化剂中是有先例的，但我们的方法利用的是尚未充分研究但价格低廉的第二族元素——碱性土。在令人兴奋的初步工作中，我们已经证明了一个简单的原型钙复合物能够催化许多底物的循环，其活性远远超过了更复杂的镧系物质。然而，这些研究也强调了我们的初始催化剂的不足；在反应过程中，它倾向于重新分配到催化不活跃的物质。我们现在希望用不太容易发生这些有害过程的催化剂来扩展这项工作。这些将利用基于吡唑和n -杂环碳给体的三足硼酸盐配体。尽管后一类配体几乎完全未被开发，但进一步的初步工作表明，该配体的强供体特性将被证明是稳定2基团中心的理想选择，而直接合成也为开发用于对映选择性催化的新手性配体带来了希望。因此，我们的建议是新颖的学术和应用动机的理想结合，将为有能力的博士候选人提供一个优秀但具有挑战性的培训环境。

The ever-increasing call upon the world's resources demands that chemists devise ever more inventive means to exploit existing and novel chemical feedstocks. The ramifications of so-called sustainable chemistry (also known as 'green chemistry') impact on all stages of the manufacturing process. This includes improving the efficiency of reactions via advances in engineering, catalysis and synthetic chemistry. Atom efficiency or the atom economy concept is an extremely useful tool for rapid evaluation of the amount of waste generated by alternative routes to a specific product. It is calculated by dividing the molecular weight of the desired product by the sum total of the molecular weights of all substances produced in the stoichiometric equation for the reaction(s) involved. This proposal seeks to develop environmentally benign catalysts for the 100% atom efficient transformation of aminoalkenes and -alkynes into valuable heterocyclic compounds. Although this type of transformation is precedented in a series of lanthanide catalysts, our approach utilises the very much understudied, but inexpensive, elements of group 2, the alkaline earths. In exciting preliminary work we have shown that a simple prototype calcium complex is capable of catalysing the cyclisation of a number of substrates with activities far exceeding those reported for more elaborate lanthanide-based species. These studies also highlighted, however, a deficiency of out initial catalyst; its tendency to redistribute to catalytically inactive species over the course of the reaction. We now wish to extend this work with catalysts that will be much less prone to these detrimental processes. These will utilise tripodal borate ligands based upon pyrazole and N-heterocyclic carbene donors. Although the latter class of ligand is almost completely unexplored, further preliminary work has indicated that the strong donor properties of the ligand will prove ideal for the stabilisation of group 2 centres, while the straightforward synthesis also holds promise for the development of new chiral ligands for enantioselective catalysis. Our proposal therefore is an ideal combination of novel academic and applied motivation that will provide an excellent, but challenging, training environment for a capable PhD candidate.