Exploring transition metal-catalysed fluorine transfer reactions

项目背景（确定问题及其对可持续性的重要性和相关性）有机氟分子是一类重要的化合物，由于C-F键的强度和高极性，它们具有多种不同的应用。C-F键存在于药物、PET成像剂、农用化学品、聚合物、光电子和许多其他高性能分子中。氟化是将氟原子添加到有机分子中的过程，由于所使用的有毒和危险的HF和元素氟试剂，在整个世纪，氟化是一项极其不安全和具有挑战性的壮举。这些方法通常具有差的选择性并且导致过度的分离。因此，在过去的二十年中，已经开发了一系列安全且易于操作的试剂，能够对药物靶标进行后期检测。然而，这些发展优先考虑选择性和控制能源和可持续性问题。这些试剂通常以令人难以置信的低原子效率反应，通常需要过量并且需要大量的能量来生产。此外，尽管这类重要的化合物对社会产生了影响，但我们对这种原材料的依赖是不可持续的。氟是一种有限的资源，几乎完全来自无机氟化物，目前的估计表明，它将维持该行业不到100年。 建议的解决方案和方法该行业需要转向使用更环保和更可持续的方法进行氟化，同时使用更便宜、更容易获得且对环境影响更小的氟化原料。近年来，多氟化合物和全氟化合物已成为一种有用的原料，因为它们很容易通过既定的工业工艺获得。这些化合物的C-F官能化提供了获得部分氟化的结构单元的途径，这些结构单元在其他方面对生产具有挑战性。目前已经开发了几种过渡金属催化、无金属催化、光催化和电催化的方法。过渡金属催化的路线主要是亲氟还原剂，如硅烷和硼烷，由于形成的强Si-F和B-F键，这导致氟从系统中损失。该项目旨在深入了解过渡金属催化的转移催化反应，努力实现氟的更循环经济。在该反应中，氟从不需要的过度氟化基材中除去，并通过过渡金属催化剂引入到需要的地方，同时产生两种有价值的产物。转移功能化反应是一种新兴的和强大的转换类，因为它们进行高原子经济和产生最小的浪费。使用可用的氟源设计有效且原子经济的氟转移反应将减轻与单一工艺中的当前脱氟和脱氟方法相关的问题。

Project background (identification of the problem and its importance and relevance to sustainability) Organofluorine molecules are an important class of compounds which find several diverse applications due to the incredible strength and high polarity of the C-F bond. C-F bonds are found within are found in pharmaceuticals, PET-imaging agents, agrochemicals, polymers, optoelectronics and many other high-performance molecules. Fluorination is the process of adding fluorine atoms to organic molecules, which throughout the 20th century was an extremely unsafe and challenging feat due to the toxic and hazardous HF and elemental fluorine reagents used. These methods often have poor selectivity and lead to over-fluorination. Therefore, over the past two decades, a portfolio of safe and easy-to-handle reagents have been developed, capable of late-stage fluorination of pharmaceutical targets. However, these developments have prioritised selectivity and control over energy and sustainability concerns. These reagents often react with incredibly low atom-efficiencies, are often required in excess quantities and require tremendous amounts of energy to produce. Furthermore, despite the impact this important class of compounds has had on society, our dependence on this raw material is unsustainable. Fluorine is a finite resource derived almost entirely from inorganic fluoride, in which current estimates suggest will sustain the industry for less than 100 years. Proposed solution and methodology The industry requires a shift towards using greener and more sustainable methods for fluorination, whilst utilising fluorinated feedstocks that are cheaper, accessible and have lower environmental impact. Over recent years, poly- and perfluorinated compounds have become a useful feedstock because they are easily accessed via established industrial processes. C-F functionalisation of these compounds gives access to partially fluorinated building blocks, that are otherwise challenging to produce. Several transition metal-catalysed, metal-free catalysed, photocatalytic and electrocatalytic routes have been developed. Transition metal-catalysed routes are dominated by fluorophilic reducing agents, such as silanes and boranes, due to the strong Si-F and B-F bonds formed, which result in the loss of the fluorine from the system. This project aims to develop insight into transition-metal catalysed transfer fluorination reactions, to strive towards a more circular economy for fluorine. In this reaction, fluorine is removed from an over-fluorinated substrate where it is not required and introduced to where it is desired via a transition-metal catalyst, yielding two valuable products simultaneously. Transfer functionalisation reactions are an emerging and powerful class of transformations as they proceed with high atom economies and produce minimal waste. The design of an efficient and atom-economic fluorine transfer reaction, using available sources of fluorine would mitigate the issues associated with current fluorination and defluorination methods in a single process.