Merging Photoredox and Ruthenium Catalysis for new C-H Activation Chemistry

这项拟议的研究旨在创造使用金属催化剂操纵C-H键的新方法。催化是现代化学的核心，90%的工业生产分子利用催化化学来合成(例如洗衣粉中的生物脂肪酶，哈伯法生产氨所用的过渡金属)。我们建议操纵有机分子中常见的C-H键，因为它们的选择性激活提供了一种在创造有价值的化学物质中产生新键的直接方式。选择性是成功的关键--我们如何激活通常装饰有机分子的C-H键森林中一棵所需的C-H‘树’？Ru催化为这一难题提供了一个令人兴奋的解决方案，早期的工作表明，对于一小部分转化，苯环上的精确C-H活化是可能的。为了将这些令人兴奋的初步结果培养成制造分子的通用工具，我们需要大幅提高对催化剂反应性的控制。我们提出了一种光驱动的解决方案来应对这一挑战-使用光化学来有效地调整催化剂，使其以正确的方式反应。有机分子通常是无色的，这意味着它们不吸收可见光。因此，光化学的学科建立在使用紫外光的基础上，紫外光被有机分子吸收，可以引发化学反应。然而，最近的发展使简单的家用灯泡的可见光能够在化学反应中得到利用。这一过程依赖于第二种催化剂来吸收光线，然后该催化剂可以与有机底物相互作用，从而实现新型化学反应。通过将C-H活化和光化学这两个催化循环合并在一起，我们提出了一个新的系统，它将极大地加速合成用于医学、工程和农业等不同应用的新分子。

The proposed research looks to create new ways of manipulating C-H bonds using metal catalysts. Catalysis is central to modern chemistry, with the synthesis of 90% of industrially-produced molecules making use of catalytic chemistry (e.g. biological lipases in washing powder, transition metals used in the Haber process to produce ammonia). We propose to manipulate C-H bonds commonly found in organic molecules, as their selective activation offers a direct way of making new bonds in the creation of valuable chemicals. Selectivity is critical to success - how do we activate the one desired C-H 'tree' in the forest of C-H bonds that typically decorate organic molecules? Ruthenium catalysis offers an exciting solution to this difficult problem, with early work showing that precise C-H activations are possible on benzene rings for a small selection of transformations. In order to grow these exciting preliminary results into a general tool for making molecules, we need to substantially improve our control of the catalyst reactivity. We propose a light-driven solution to this challenge - using photochemistry to effectively tune the catalyst to react in the right way. Organic molecules are typically colourless, meaning they do not absorb visible light. As a result, the discipline of photochemistry is founded upon the use of UV light, which is absorbed by organic molecules and can initiate chemical reactions. Recent developments, however, have enabled visible light from simple domestic lightbulbs to be harnessed in chemical reactions. The process depends on a second catalyst to absorb the light, which can then interact with the organic substrates to enable new types of chemical reaction. By merging these two catalytic cycles together, C-H activation and photochemistry, we propose a new system that will dramatically accelerate the synthesis of new molecules for diverse applications in medicine, engineering and agriculture.