Development of Palladium-catalyzed cross-coupling reactions of aryl halides with organosodium and potassium compounds

S-区金属有机化合物如有机锂或格氏试剂是合成化学中最重要的有机金属化合物之一，并且通常用作去质子化和金属化反应中的强碱。相比之下，它们在过渡金属催化的C-C偶联反应中的应用较少。这对于反应性更强（更重）的碱金属有机化合物尤其如此，其更经常发生不期望的副反应，从而减少或甚至防止产物形成。本研究计画的目标是发展以钯为催化剂，将极性有机金属化合物与芳基卤化物直接偶联。因此，C-C键的形成将在没有额外的金属转移步骤的情况下实现，从而节省了昂贵且有毒的金属转移试剂和盐废物的产生。直到今天，较重的碱金属有机化合物的这种转化非常有限，或者用目前存在的催化剂根本不可行。因此，这种限制将通过开发基于叶立德取代的膦的新催化剂来解决。由于它们的分子设计，这些配体特别富含电子，因此应该非常适合掌握这些转化。主要重点将放在钾和钠的有机化合物，这几乎没有在耦合化学中使用，但提供了新的或尚未应用的亲核试剂的使用。开发的协议将特别针对芳基氯的使用，因为它们的成本较低，丰度更广。总的来说，该项目将为高活性极性有机金属化合物的偶联设定新的标准，从而缩小偶联和s区金属化学的差距。

S-Block metal organyls such as organolithium or Grignard reagents are amongst the most important organometallic compounds in synthetic chemistry and are routinely employed as strong bases in deprotonation and metallation reactions. In contrast, their application in transition metal catalyzed C-C coupling reactions is less developed. This is particularly true for the more reactive (heavier) alkalimetal organyls, which more often undergo undesired sidereactions, thus reducing or even preventing product formation. Goal of the research project is the development of the direct coupling of polar organometallic compounds with aryl halides by means of palladium catalysis. Thereby, the C-C bond formation shall be realized without additional transmetallation step, thus saving expensive and toxic transmetallation reagents and the generation of salt waste. Until today, such transformations of the heavier alkali metal organyls are very limited or not feasible at all with so far existing catalysts. Thus, this limitation will be addressed by development of new catalysts based on ylide-substituted phosphines. Due to their molecular design these ligands are especially electron-rich and thus should be perfectly suited to master these transformations. Main focus will be set on potassium and sodium organyls, which have hardly been employed in coupling chemistry but offer the use of new or not yet applied nucleophiles. The developed protocol will particularly target the use of aryl chlorides due to their lower costs and broader abundance. Overall, this project will set new standards in the coupling of highly reactive polar organometallic compounds and hence close a gap in coupling and s-block metal chemistry.