Onium Ions in (Photo)Catalysis for Organic Synthesis

化学的进步要求科学家设计具有特定结构和性质的分子实体。因此，这项提议将开发和实施一种创新的战略，以组装分子，并在从后期官能化化学到不对称催化的高影响合成领域得到广泛应用。我们的策略使用现成的洋葱盐作为关键，以实现具有天然丰富官能团的成对偶联伙伴的结合，从而打开获得新化学结构的大门。我们将首先介绍硫酸盐在自由基化学中作为化学关键分子的用途，允许带有天然丰富官能团的复杂分子(羧酸、醇、胺)与各种伙伴之间的选择性交叉偶联。因此，我们将通过设计一种新的光催化策略(双氢原子转移催化)来将我们的离子偶联策略扩展到复杂分子的选择性SP3C-H官能化，该策略对自由基C-H活化化学具有普遍的适用性。然后，我们将把我们的策略的适用性扩大到烯烃和杂芳烃的选择性后期官能化，这是生物分子中经常出现的主题。为了实现这一雄心勃勃的目标，我们将介绍新的活性中间体在合成中的应用，最后，我们将通过创建一种新的方法来锻造对映体富集手性小分子来展示该策略的更广泛的合成应用，这是合成中有价值的材料。也就是说，我们将通过设计合适的催化策略，介绍在不对称催化中通过手性连接中心连接元素构建块的使用。总而言之，这项提议提出了一种组装化学结构的全新方法，有望促进科学技术各个领域的重大长期进步。

Advances in chemistry require scientists to design molecular entities with specific structures and properties. This proposal will therefore develop and implement an innovative strategy to assemble molecules with broad application in high-impact areas of synthesis, from late-stage functionalisation chemistry to asymmetric catalysis. Our strategy uses readily available onium salts as linchpins to achieve the union of pairs of coupling partners bearing naturally abundant functional groups, thus unlocking access to new chemical structures. We will first introduce the use of sulfonium salts as chemical linchpins in radical chemistry, allowing the selective cross-coupling between complex molecules carrying naturally abundant functional groups (carboxylic acids, alcohols, amines) and a variety of partners. Thus, we will extend our onium-coupling strategy to the selective sp3 C-H functionalisation of complex molecules by designing a novel photocatalytic strategy (dual hydrogen atom transfer catalysis) with general applicability for radical C-H activation chemistry. We will then broaden the applicability of our strategy to the selective late-stage functionalisation of olefins and heteroaromatics, which are recurrent motifs in biomolecules. To achieve this ambitious goal, we will introduce the use of novel reactive intermediates in synthesis (onium radicals).Finally, we will demonstrate the strategy's broader synthetic application by creating a new approach to forge enantioenriched small chiral molecules, which are valuable materials in synthesis. Namely, we will introduce the use of onium salts in asymmetric catalysis to connect elemental building blocks through chiral conjunctive centres by designing appropriate catalytic strategies. In conclusion, this proposal presents a fundamentally new way to assemble chemical structures that is expected to promote dramatical long-term advances in various fields of Science and Technology.