Dinuclear and ansa-titanocenes for enantioselective catalyst-controlled radical reactions and further applications

用于对映选择性催化剂控制的自由基反应的双核和柄型二茂钛及其进一步应用

• 批准号: 333382543
• 负责人: Professor Dr. Jan Streuff
• 金额: --
• 依托单位: Institutionen för kemi
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/333382543?language=en
• 关键词: Dinuclear; ansa; titanocenes; enantioselective; catalyst

Radical reactions play a crucial role in polymerization reactions and, more recently, are becoming increasingly important in well-defined C-C bond forming reactions. Realizing catalytic enantioselective radical reactions, however, has remained problematic. Recently, we demonstrated that radical cyclizations of ketonitriles run in presence of a chiral ansa-titanocene catalyst proceed with exceptional enantioselectivity and, thus, with excellent catalyst control. Based on our mechanistic studies, we herein propose the development of chiral dinuclear titanocene catalysts for the realization of further intra- and intermolecular enantioselective radical reactions. This includes new strategies for the synthesis of chiral-bridged cyclopentadienyl (Cp) ligands. Our approach will further lead to rapid and stereoselective syntheses of chiral ansa-titanocenes and Cp-complexes of other metals, which we will evaluate in typical applications and novel reactions. This way, we will overcome several classical problems in metallocene synthesis and significantly broaden the application range of such catalysts.

自由基反应在聚合反应中起着至关重要的作用，并且最近在明确的 C-C 键形成反应中变得越来越重要。然而，实现催化对映选择性自由基反应仍然存在问题。最近，我们证明了酮腈的自由基环化在手性柄型二茂钛催化剂存在下进行，具有优异的对映选择性，因此具有出色的催化剂控制。基于我们的机理研究，我们在此提出开发手性双核二茂钛催化剂，以实现进一步的分子内和分子间对映选择性自由基反应。这包括合成手性桥联环戊二烯基 (Cp) 配体的新策略。我们的方法将进一步实现手性柄二茂钛和其他金属的 Cp 配合物的快速立体选择性合成，我们将在典型应用和新颖反应中对其进行评估。这样，我们将克服茂金属合成中的几个经典问题，并显着拓宽此类催化剂的应用范围。