Photoredox Catalyzed Remote C(sp3)–H Trifluoromethylation

光氧化还原催化远程 C(sp3)âH 三氟甲基化

• 批准号: 435885260
• 负责人: Dr. Francis Forster
• 金额: --
• 依托单位: Department of Chemistry
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/435885260?language=en
• 关键词: Photoredox; Catalyzed; Remote; sp3; Trifluoromethylation

We plan to develop a photoredox-catalyzed trifluoromethylation of remote unactivated C(sp3)–H bonds intramolecularly directed by an amide group. We propose that this catalysis proceeds via oxidation of an in-situ-formed amidyl anion by a metal-based photocatalyst, which undergoes quickly a 1,5-hydrogen atom transfer. The resulted carbon-centered radical can be coupled with a trifluoromethyl radical by another transition metal catalyst via radical cross-coupling. Optimization studies will include screenings of trifluoromethylating reagents, used solvents and bases, as well as screenings of the photocatalysts and cross-coupling catalysts. Our final plans are to expand this methodology toward intermolecular trifluoromethylation of secondary C(sp3)–H bonds in simple alkanes by an intermolecular hydrogen abstraction. Moreover, the fluorination of unactivated C(sp3)–H bonds would be of similar interest to us. Analytical methods like cyclic voltammetry and Stern-Vollmer experiments should help elucidating the reaction mechanism of this catalysis.

我们计划开发一种由酰胺基团引导的分子内远程未激活 C(sp3)-H 键的光氧化还原催化三氟甲基化。我们提出这种催化作用是通过金属基光催化剂氧化原位形成的酰胺基阴离子来进行的，该催化剂快速进行 1,5-氢原子转移。所得的碳中心自由基可以通过另一种过渡金属催化剂通过自由基交叉偶联与三氟甲基自由基偶联。优化研究将包括三氟甲基化试剂、所用溶剂和碱的筛选，以及光催化剂和交叉偶联催化剂的筛选。我们的最终计划是将这种方法扩展到简单烷烃中二级 C(sp3)-H 键的分子间三氟甲基化，通过分子间氢提取。此外，我们对未活化的 C(sp3)-H 键的氟化也有类似的兴趣。循环伏安法和斯特恩-沃尔默实验等分析方法应该有助于阐明这种催化的反应机制。