Harnessing Electron-Donor-Acceptor Complexes to Enable Photo-Induced Metal-Free Cross-Coupling Reactions

项目总结/摘要 有机分子和结构单元中丰富的C（sp3）-H键，使得直接官能化 这些结构的一个非常有吸引力的和强大的工具，合成和后期功能化的 大药厂不幸的是，目前实现这些转化的方法使用金属催化剂， 不符合可持续发展要求的试剂。类似地，烷基卤化物是其中之一。 在有机化学中使用的最大的商业上可获得的结构单元组，但是庞大的叔烷基 卤化物不能容易地用作烷基化剂，因为它们不能进行SN 2过程。因此，我们认为， 开发无过渡金属和与当前方法正交的策略， C-H和C-X键将是一个重大贡献，因为它解决了一个未满足的需求。 最近，电子给体受体（EDA）配合物作为光诱导的光致发光材料的应用已经得到了关注。 在其他非反应性试剂之间进行单电子转移的方法。不幸的是，目前 通过EDA络合物进行的反应不利用所形成的自由基来进行氢- 原子转移（HAT）和卤素原子转移（XAT）过程，可以使用丰富的 上述化学原料。 拟议调查的研究目标有望解决上述障碍， 建立EDA复合物作为光诱导烷烃自由基活化的尖端策略， 烷基卤化物。我们在概念上的创新假设是空间和电子调谐的芳基自由基 从EDA复合物产生的可用于实现位点选择性HAT和XAT过程。所得 然后将产生的烷基偶联以实现对映体和非对映体选择性交叉偶联。这 工作将使用计算模型来支持、指导和加速EDA的设计和发现 芳烃的配合物。这些探索将建立新的平台， 交叉偶联和XAT介导的偶联，其形成挑战性C（sp3）-C（sp3）键。

Project Summary/Abstract The abundance of C(sp3)–H bonds in organic molecules and building blocks, makes the direct functionalization of these structures a very attractive and powerful tool for the synthesis and late-stage functionalization of pharmaceuticals. Unfortunately, current methods to achieve these transformations use metal-catalysts and reagents that do not meet requirements for sustainable development. Similarly, alkyl halides are among the largest groups of commercially available building blocks used in organic chemistry, but bulky tertiary alkyl halides cannot be easily used as alkylating agents because they cannot undergo SN2 processes. Therefore, the development of strategies that are transition-metal-free and orthogonal to current approaches to activate C–H and C–X bonds would be a significant contribution as it addresses an unmet need. Recently, the application of electron-donor-acceptor (EDA) complexes has gained attention as a photo-induced method to perform single electron transfers between otherwise unreactive reagents. Unfortunately, current reactions that proceed via EDA complexes do not take advantage of the formed radicals to perform hydrogen- atom-transfer (HAT) and halogen-atom-transfer (XAT) processes that could enable the use of the abundant chemical feedstock mentioned above. The research objectives of the proposed investigations promise to tackle the above-cited barriers to help establish EDA complexes as a cutting-edge strategy for the photo-induced radical-activation of alkanes and alkyl halides. Our conceptually innovative hypothesis is that sterically and electronically tuned aryl radicals generated from EDA complexes can be used to achieve site-selective HAT and XAT processes. The resulting alkyl radicals generated are then coupled to achieve enantio- and diastereoselective cross-couplings. This work will use computational models to support, guide, and accelerate the design and discovery of EDA complexes of arenes. These explorations will establish new platforms that enable enantio- and regioselective cross-dehydrogenative couplings, and XAT mediated couplings that form challenging C(sp3)–C(sp3) bonds.