Synthesis of multiply bonded main-group compounds for small molecule activation reactions

用于小分子活化反应的多键主族化合物的合成

• 批准号: 2605012
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2605012
• 关键词: Synthesis; multiply; bonded; main; group

Amines play an important role in a variety of industries, including in agriculture and the pharmaceutical sector. Although amines can be easily synthesised on a laboratory scale, these synthetic protocols are often unattractive to industry, usually due to safety concerns with precursors or atom inefficient methodologies. By contrast, hydroamination (the addition of ammonia across an unsaturated substrate, such as an alkene or alkyne) is an attractive process for the synthesis of value-added chemicals such as fertilisers in an sustainable fashion. Despite the attractive nature of this process, ammonia is a challenging substrate, and to date there are no known catalysts which can use it as a feedstock. Transition metal catalysts typically fail in effecting hydroamination because of their propensity to form Werner complexes with ammonia which precludes N-H bond activation. In contrast, main-group systems are an attractive alternative to transition metals as they are more Earth-abundant and less likely to form unreactive ammonia adducts, but their catalytic behaviour is less well explored. Clearly, the development of a viable hydroamination catalyst is an important step towards reducing the cost and waste of amine synthesis. Recently, the Goicoechea group has synthesised novel species containing P-Ga double bonds (known as phosphagallenes). Their ability to act as a frustrated Lewis pair (FLP) and activate a variety of N-H bonds, including that of ammonia has also been demonstrated; these join the approximately dozen examples of single-site N-H bond activation using main-group systems. The goal of this project is to exploit this unusual reactivity in cooperative catalysis with transition metals, paving the way for the synthesis of amine substrates from inexpensive and widely available ammonia feedstocks. The project aims to synthesise novel species containing group 13/15 element multiple bonds and to study the behaviour of such compounds in small-molecule activation reactions, with a particular focus on amines. Further, the project will probe the viability of these novel compounds in catalytic hydroamination reactions of unsaturated species, such as alkenes and alkynes. Traditionally, small-molecule activation is largely limited to transition metals. Although these elements have widespread application in catalysis, this does not extend to the catalytic hydroamination of ammonia; only a single example based on Au(I) is presently known. By contrast, a number of main-group compounds have been shown to stoichiometrically activate ammonia, but catalysis with main-group systems is limited to the alkaline-earth metals and only with more substituted amines. The aim of this project is to exploit the novel behaviour of phosphagallenes in catalytic hydroamination. This project falls within the EPSRC Catalysis research area, which directly contributes to the Manufacturing the Future and Physical Sciences research themes.

胺在包括农业和制药部门在内的各种工业中发挥着重要作用。虽然胺可以很容易地在实验室规模上合成，但这些合成方案往往对工业没有吸引力，通常是由于对前体的安全问题或原子效率低下的方法。相比之下，氢胺化（在不饱和底物上添加氨，如烯烃或炔）是一种有吸引力的方法，可以以可持续的方式合成增值化学品，如化肥。尽管这一过程具有吸引力，但氨是一种具有挑战性的底物，迄今为止还没有已知的催化剂可以将其用作原料。过渡金属催化剂通常不能影响氢胺化，因为它们倾向于与氨形成维尔纳配合物，这阻碍了N-H键的激活。相比之下，主基团体系是过渡金属的一个有吸引力的替代品，因为它们在地球上更丰富，不太可能形成非反应性氨加合物，但它们的催化行为尚未得到很好的探索。显然，开发可行的氢胺化催化剂是降低胺合成成本和浪费的重要一步。最近，Goicoechea小组合成了含有P-Ga双键的新物种（称为磷酸二烯）。它们作为受挫路易斯对（FLP）并激活各种n -氢键（包括氨的）的能力也已被证明；这些加入了大约十几个使用主基团系统激活单位点N-H键的例子。该项目的目标是利用这种不寻常的反应性与过渡金属的协同催化，为从廉价和广泛可用的氨原料合成胺底物铺平道路。该项目旨在合成含有13/15组元素多键的新物种，并研究这些化合物在小分子活化反应中的行为，特别关注胺。此外，该项目将探索这些新化合物在催化不饱和物种（如烯烃和炔烃）的氢胺化反应中的可行性。传统上，小分子活化主要局限于过渡金属。虽然这些元素在催化中有广泛的应用，但这并没有延伸到氨的催化氢胺化；目前已知的基于Au(I)的例子只有一个。相比之下，许多主基团化合物已被证明可以在化学计量上激活氨，但主基团系统的催化作用仅限于碱土金属，并且只能与更多的取代胺。本项目的目的是利用磷酸二烯在催化氢胺化中的新行为。该项目属于EPSRC催化研究领域，直接有助于未来制造和物理科学研究主题。