Artificial photosynthesis strategies for synthesis: Combined photoredox and transition metal-catalysed transfer hydrogenation of C-C multiple bonds

人工光合作用合成策略：结合光氧化还原和过渡金属催化的 C-C 多重键转移氢化

• 批准号: EP/V048961/1
• 负责人: Xacobe Cambeiro
• 金额: $ 25.8万
• 依托单位: University of Greenwich
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FV048961%2F1
• 关键词: Artificial; photosynthesis; strategies; synthesis; Combined

The feasibility of chemical reactions is generally governed by the existence of a sufficient thermodynamic driving force pushing them. When performing sequences of reactions to prepare compounds of interest, this driving force is ensured by using in each step highly reactive small molecule reactants with a high energy contents, and the availability and procedence of such reactants determine the limits of how practical and sustainable a chemical process can be. Illustrative examples are oxidations and reductions, two of the main categories in which we classify chemical reactions. In the case of oxidation reactions, molecular oxygen can be used an ideal oxidant, since it is abundant and innocuous and in ideal conditions it can be consumed to produce only water as a by-product. Similarly, we could conceive using water as an ideal reductant, which would result in production of only oxygen as by-product. However, this faces the problem of water not being a good reductant or, in other words, lacking the thermodynamic driving force needed to push the reaction. Instead, the most common reductant used for organic compounds is molecular hydrogen, which is not found in nature and is instead produced in an overwhelming majority from fossil fuels in a process that releases enormous amounts of carbon dioxide.Remarkably, photosynthetic organisms use water as the reductant in the fixation of carbon dioxide to form carbohydrates and release molecular oxygen, with sunlight providing the required energy. Taking inspiration from this, in this proposal we aim to develop an 'artificial photosynthesis' approach for the reduction of certain types of organic compounds of industrial importance -namely, alkenes and alkynes. To do this, we will need to develop systems where two catalysts operate in a concerted manner, with one using the energy from light to oxidise water (forming oxygen and providing the 'reductive power') and the other reducing the organic compound. Catalysts are already known capable of performing the first of these roles, and in this project we will develop the second, thus bridging the key gap to enable true artificial photosynthesis reactions in organic chemistry.This investigation will result in more sustainable methods for reduction of alkenes and alkynes which, importantly, are among the largest scale organic reactions performed in chemical industry. Thus, success in this project will contribute towards the development of a more sustainable chemical industry in general, reducing its dependence on the use of fossil sources of carbon. Also, this investigation will produce valuable information on the mechanistic manifolds involved, thus providing facilitating the discovery of other efficient and sustainable reactions in the future.

化学反应的可行性通常受到推动的足够热力学驱动力的存在。当执行反应序列以制备感兴趣的化合物时，通过在每个步骤中使用高反应性的小分子反应物具有高能量含量，并且这些反应物的可用性和过程确定了化学过程的实用和可持续性的限制。说明性的例子是氧化和减少，这是我们对化学反应进行分类的两个主要类别。在氧化反应的情况下，可以将分子氧用于理想的氧化剂，因为它丰富且无害，并且在理想条件下，它可以仅生产水作为副产品。同样，我们可以构想使用水作为理想还原剂，这将导致仅生产氧作为副产品。但是，这面临水的问题不是良好的还原剂，或者换句话说，缺乏推动反应所需的热力学驱动力。取而代之的是，用于有机化合物的最常见的还原剂是分子氢，在自然界中找不到，而在绝大多数中产生的是化石燃料的绝大多数，在一个过程中，释放了二氧化碳的碳含量大量，可释放的光合生物在氧化二氧化碳中释放，以释放氧化物的固定量和固定在氧化氧化范围内，以释放氧化物的固定量，并将其固定在氧化二氧化碳中，以使氧化氧化氧化物的固定层均匀固定在碳水化合物中均匀的氧化二氧化碳。提供所需的能量。从中汲取灵感，在此提案中，我们旨在开发一种“人造光合作用”方法，以减少某些类型的工业重要性有机化合物 - 碱和炔烃。为此，我们将需要开发两个催化剂以协同方式运行的系统，一种催化剂使用从光到氧化水（形成氧气并提供“还原能力”），而另一个则减少了有机化合物。催化剂已经众所周知能够执行这些角色的第一个角色，在这个项目中，我们将开发第二个角色，从而弥合了有机化学中真正的人造光合作用反应的关键差距。这项研究将导致更具可持续性的方法来减少烯烃和炔烃的减少，这是重要的，重要的是，在化学量表中很重要。因此，该项目的成功将有助于总体上更可持续的化学工业的发展，从而减少其对化石源使用碳源的依赖。此外，这项调查将提供有关所涉及的机械歧管的有价值的信息，从而促进将来发现其他高效和可持续的反应。