HYDROAMINATION OF ALKENES AND ALKYNES WITH GROUP 2-CENTRED CATALYSTS

对世界资源的不断增长的需求要求化学家设计出更具创造性的方法来利用现有的和新的化学原料。所谓的可持续化学（也称为“绿色化学”）的分支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效率。原子效率或原子经济概念是一个极其有用的工具，可用于快速评估通过替代途径生产特定产品所产生的废物量。其计算方法是将所需产物的分子量除以所涉及反应的化学计量方程中产生的所有物质的分子量总和。该建议旨在开发环境友好的催化剂，用于100%原子有效地将氨基烯烃和-炔转化为有价值的杂环化合物。尽管这种类型的转化在一系列镧系元素催化剂中是先例，但我们的方法利用了研究不足但价格低廉的第2族元素碱土金属。在令人兴奋的初步工作中，我们已经表明，一个简单的原型钙络合物能够催化许多底物的环化，其活性远远超过了更复杂的镧系元素为基础的物种的报道。然而，这些研究也强调了初始催化剂的不足之处;其在反应过程中倾向于重新分布为催化惰性物质。我们现在希望用更不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-杂环卡宾供体的三脚架硼酸盐配体。虽然后一类的配体几乎是完全未开发的，进一步的初步工作表明，强大的供体性质的配体将被证明是理想的第2组中心的稳定，而简单的合成也有希望发展新的手性配体的对映选择性催化。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.