Novel chiral carbenes based on camphoric acid for asymmetric catalysis

基于樟脑酸的新型手性卡宾用于不对称催化

• 批准号: 168106543
• 负责人: Professor Dr. René Wilhelm
• 金额: --
• 依托单位: Institut für Organische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/168106543?language=en
• 关键词: Novel; chiral; carbenes; based; camphoric

The proposal deals with the development of new chiral carbenes, which are based on camphoric acid. Due to this cheap chiral precursor, the desired ligands can be prepared in a few steps on a large scale. The NCN unit is embedded in a rigid bicyclic system being part of a six and seven-membered ring. Hence, the corresponding carbenes possess a higher basicity than carbenes with imidazolium and imidazolinium moieties, which is desirable in many catalytic applications. In addition, the free rotation of substituents next to the C(10) methyl group of the camphor skeleton is limited due to steric hindrance, which provides an asymmetric differentiation in a catalytic reaction step. The application of camphoric acid provides an easy route to six-membered ring carbenes with chiral information in the backbone. The introduction of useful chiral information for asymmetric catalysis in the backbone of a six-membered ring carbene is normally difficult. The new carbenes will be investigated in catalysis with a range of metals focusing in the beginning on Pd(II) and Pd(IV) catalyzed reactions. In addition, the application of the new ligands in metatheses reactions will be explored. Furthermore, it has been already shown that these carbenes can be used as organocatalysts in a [2+2] cycloaddition and their application will be extended in related reactions.

该提案涉及以樟脑酸为基础的新型手性碳烯的开发。由于这种廉价的手性前体，所需的配体可以在几个步骤中大规模制备。NCN单元嵌入在刚性双环系统中，是六元和七元环的一部分。因此，相应的碳烯比咪唑和咪唑基的碳烯具有更高的碱度，这在许多催化应用中是理想的。此外，樟脑骨架C（10）甲基附近取代基的自由旋转由于位阻而受到限制，这在催化反应步骤中提供了不对称分化。樟脑酸的应用为合成具有手性信息的六元环碳烯提供了一条简单的途径。在六元环羰基的主链中引入有用的手性信息进行不对称催化通常是困难的。新的碳烯将在钯（II）和钯（IV）催化反应中与一系列金属的催化作用进行研究。此外，还将探讨新配体在复合反应中的应用。此外，已有研究表明，这些化合物可作为[2+2]环加成反应的有机催化剂，并将在相关反应中得到广泛应用。