Redoxneutral Propargylic CH-Activation: from Mechanistic Investigations towards better Catalysts

氧化还原中性炔丙 CH 活化：从机理研究到更好的催化剂

• 批准号: 244311015
• 负责人: Professor Dr. Bernhard Breit
• 金额: --
• 依托单位: Leibniz-Institut für Katalyse e. V. an der Universität Rostock (LIKAT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/244311015?language=en
• 关键词: Redoxneutral; Propargylic; CH; Activation; Mechanistic

With this project the mechanistic investigations on rhodium catalyzed propargylic C-H-activation shall be continued. With the atom economic, redox neutral catalysis in question, allylic esters and enolesters can be synthesized starting form carbon acids and terminal alkynes or allenes. In the synthesis of branched allylic esters with DIOP as chiral ligand enantiomeric excesses up to 96% can be achieved. In the cooperation of B. Breit and D. Heller, the resting state of the catalytic cycle was identified. This key intermediate was characterized by means of NMR- and Raman spectroscopy, as well as by X-ray analysis and mass spectrometry. In addition, a qualitative rate law for the catalytic transformation was determined through in-situ IR- and NMR-spectroscopy. In these investigations a catalyst inhibition in reactions with the alkyne substrate was detected. The experiments were supported by DFT-calculations, which matched the findings. The results obtained in this collaboration were used to refine the proposed mechanism. The successful cooperation of B. Breit and D. Heller will be continued on basis of the project presented here. The main objectives of this project are further mechanistic investigations of the formation of esters as well as the transferability of the proposed mechanism to the analogous rhodium catalyzed formation of allylic amines with nitrogen-containing pronucleophiles. Within this project the effects of alkynes and allenes on the catalytic reaction, especially the origin of the inhibition of the catalyst, will be examined. In addition, an explanation for the observed chemoselectivity towards different ester products depending on the chosen ligand shall be elaborated and the relation of the product to the structure of the rhodium ligand complex shall be investigated. The mechanistic investigations of the rhodium catalyzed formation of allylic amines with anilines and benzotriazoles shall indicate whether the proposed mechanisms for the different pronucleophiles share a common base or if every pronucleophile has its own unique mechanism. During the investigations of the addition of the benzotriazole to terminal allenes, a reason for the observed regioselectivity towards the N1- and N2-product depending on the ligand will be saught after. The mechanistic investigations will consist of NMR-, IR-, UV/Vis-, and Raman-spectroscopic, crystallographic and mass spectrometric experiments and will be complemented with DFT calculations.

本项目将继续开展铑催化炔丙基C-H-活化的机理研究。利用原子经济、氧化还原中性催化，可以由碳酸和末端炔或联烯合成烯丙酯和烯醇酯。以DIOP为手性配体合成支链烯丙基酯，对映体过量可达96%。在B的合作下。Breit和D. Heller，确定了催化循环的静止状态。通过NMR和拉曼光谱以及X射线分析和质谱对该关键中间体进行了表征。此外，通过原位IR和NMR光谱确定了催化转化的定性速率定律。在这些研究中，检测到与炔底物反应中的催化剂抑制。这些实验得到了DFT计算的支持，这与研究结果相匹配。在这次合作中获得的结果被用来完善拟议的机制。B的成功合作。Breit和D.海勒将继续在这里提出的项目的基础上。该项目的主要目标是进一步的酯的形成机制的调查，以及拟议的机制的可转移性类似铑催化形成烯丙基胺与含氮亲核试剂。在这个项目中，炔和联烯对催化反应的影响，特别是催化剂的抑制的起源，将被检查。此外，应详细说明所观察到的化学选择性对不同的酯产品取决于所选择的配体的解释和铑配体络合物的结构的产品的关系进行调查。铑催化的烯丙基胺与苯胺和苯并三唑形成的机理研究应表明不同亲核试剂的拟议机理是否有共同的基础，或者每个亲核试剂都有自己独特的机理。在研究苯并三氮唑对末端联烯的加成反应过程中，我们发现了N1-和N2-产物的区域选择性取决于配体的原因。机理研究将包括NMR-，IR-，UV/维斯-和拉曼光谱，晶体学和质谱实验，并将补充DFT计算。