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.

根部反应在聚合反应中起着至关重要的作用，最近，在定义明确的C-C键形成反应中变得越来越重要。但是，意识到催化对映选择性自由基反应仍然存在问题。最近，我们证明了在手性ANSA-titantanecene催化剂存在下进行具有出色的对映选择性，因此具有出色的催化剂对照，酮生腈的根治性环化进行。基于我们的机械研究，我们在这里提出了手性二核钛催化剂的发展，以实现进一步的分子内和分子间对照对映选择性自由基反应。这包括合成手性桥式环烷基（CP）配体的新策略。我们的方法将进一步导致其他金属的手性ANSA-titanocenes和CP复合物的快速和立体选择性合成，我们将在典型的应用和新反应中进行评估。这样，我们将克服甲金属合成中的几个经典问题，并显着扩大此类催化剂的应用范围。