亲核芳族氟化 (S N Ar) 是形成 C(sp 2 )-F 键的最常用方法之一。尽管最近取得了许多进展,但这些转化的长期限制是需要严格干燥的非质子条件来保持氟化物的亲核性并抑制副产物的产生。本报告通过利用四甲基氟化铵醇加合物 (Me 4 NF·ROH) 作为 S N Ar 氟化的氟化物来源解决了这一挑战。通过系统调整醇取代基 (R),四甲基氟化铵叔戊醇 (Me 4 NF· t-AmylOH) 被确定为在温和方便的条件下(DMSO 中 80°C,无需干燥试剂或溶剂)下用于 S N Ar 氟化的廉价、实用且台式稳定的试剂。展示了超过 50 种(杂)芳基卤化物和硝基芳烃亲电子试剂的底物范围。
Molecules labeled with fluorine-18 (18F) are used in positron emission tomography to visualize, characterize and measure biological processes in the body. Despite recent advances in the incorporation of 18F onto arenes, the development of general and efficient approaches to label radioligands necessary for drug discovery programs remains a significant task. This full account describes a derisking approach
One aspect of the invention relates to a metal-catalyzed conversion of aryl halides and sulfonates to the corresponding aryl fluorides. Another aspect of the invention relates to a metal-catalyzed conversion of heteroaryl halides and sulfonates to the corresponding heteroaryl fluorides. Another aspect of the invention relates to a metal-catalyzed conversion of vinyl halides and sulfonates to the corresponding vinyl fluorides. In certain embodiments, simple fluoride sources, such as AgF and CsF, are used. In certain embodiments, the transformations tolerate a wide range of functional groups, allowing for introduction of fluorine atoms into highly functionalized organic molecules.
One-step hydroxylation of aryl and heteroaryl fluorides using mechanochemistry
作者:Eduardo Rodrigo、Rainer Wiechert、Magnus W. Walter、Wilfried Braje、Hervé Geneste
DOI:10.1039/d1gc04361g
日期:——
Simple use of KOH allows the direct F to OH exchange of aromatic and heteroaromatic substrates under mechanochemical conditions. The reaction is performed in the absence of solvent with potassiumhydroxide as OH source. As a result, this approach is both more atom economical and environmentally friendly than previously described methods for this transformation.
简单地使用 KOH 可以在机械化学条件下实现芳族和杂芳族底物的直接 F 到 OH 交换。该反应在没有溶剂的情况下以氢氧化钾作为OH源进行。因此,这种方法比之前描述的这种转化方法更原子经济和环境友好。
Accelerating Palladium-Catalyzed CF Bond Formation: Use of a Microflow Packed-Bed Reactor
作者:Timothy Noël、Thomas J. Maimone、Stephen L. Buchwald
DOI:10.1002/anie.201104652
日期:2011.9.12
A flow process for Pd‐catalyzed CFbondformation is described. A microreactor with a packed‐bed design allows for easy handling of large quantities of insoluble CsF with precise control over reaction times, efficient mixing, and the ability to safely handle elevated temperatures and pressures. A variety of aryl triflates, including heteroaryl ones, were converted into aryl fluorides in short reaction
描述了 Pd 催化的C F 键形成的流动过程。具有填充床设计的微反应器可以通过精确控制反应时间、有效混合以及安全处理高温和高压的能力轻松处理大量不溶性 CsF。各种芳基三氟甲磺酸酯,包括杂芳基三氟甲磺酸酯,在很短的反应时间内被转化为芳基氟化物(参见方案)。