Sodium Diisopropylamide in Tetrahydrofuran: Selectivities, Rates, and Mechanisms of Arene Metalations
作者:Russell F. Algera、Yun Ma、David B. Collum
DOI:10.1021/jacs.7b08734
日期:2017.10.25
Sodium diisopropylamide (NaDA)-mediated metalations of arenes in tetrahydrofuran (THF)/hexane or THF/Me2NEt solutions are described. A survey of >40 benzenoid- and pyridine-based arenes with a range of substituents demonstrates the efficacy and regioselectivity of metalation. Metalations of activated disubstituted arenes and selected monosubstituted arenes are rapid at −78 °C. Rate studies of 1,3-dimethoxybenzene
描述了在四氢呋喃(THF)/己烷或THF / Me 2 NEt溶液中,二异丙基氨基钠(NaDA)介导的芳烃金属化。对超过40种具有一系列取代基的基于苯并吡啶和吡啶的芳烃的研究表明,其金属化的功效和区域选择性都很高。活化的二取代的芳烃和选定的单取代的芳烃在-78°C时快速金属化。1,3-二甲氧基苯和相关甲氧基化芳烃的速率研究表明,基于单体的原金属具有两个或三个配位的THF配体。苯和具有弱活化基团的单取代芳烃的同位素交换速率研究表明,类似的二溶剂化和三溶剂化的单体基金属化反应。讨论了协同的诱导,消旋,空间和螯合作用。
The thermal conversions of 6,6-difluorobicyclo[3.1.0]hex-2-enes to fluorobenzenes. An interesting dichotomy of mechanisms
1.0]hex-2-ene systems led to the conclusion that drastically different mechanisms operate for the two reactions. Activation parameters, solvent effects, kinetic isotope effects, isotope labelling experiments and observation of reactive intermediates all contributed to the conclusion that the reaction of 6,6-difluorobicyclo[3.1.0]hex-2-ene, 1, proceeds via a homolytic hydrogen-shift rearrangement, while
Exchange Reactions of Deuterated Benzene Derivatives with Potassium Amide in Liquid Ammonia<sup>1a</sup>
作者:George E. Hall、Richard Piccolini、John D. Roberts
DOI:10.1021/ja01622a033
日期:1955.9
The rates of deuterium-protium exchange have been determined for o-, m- and p-deuterated fluorobenzene, benzotri-fluoride and anisole in liquidammonia solution in the presence of potassiumamide. The exchange rates were found to be greatest for the ortho compounds and smallest for the para compounds. Deuterobenzene and o-deuterotoluene reacted too slowly for convenient measurement. The results are
Diphenyliodonium-Catalyzed Fluorination of Arynes: Synthesis of<i>ortho</i>-Fluoroiodoarenes
作者:Yuwen Zeng、Guangyu Li、Jinbo Hu
DOI:10.1002/anie.201503308
日期:2015.9.7
Described is a one‐pot vicinal fluorination‐iodination of arynes at room temperature. The diphenyliodonium salt proved to be a privileged catalyst for this nucleophilic fluorination process using CsF as a fluorine source, and a subsequent facile electrophilic iodination with C4F9I was also found to be crucial to ensure the efficient fluorination. This new synthetic protocol has a broad substrate scope
描述了室温下一锅的芳烃邻位氟化碘。在使用CsF作为氟源的亲核氟化过程中,二苯基碘鎓盐被证明是一种优先的催化剂,随后发现用C 4 F 9 I进行简便的亲电子碘化对于确保有效的氟化也至关重要。这种新的合成方案在温和的反应条件下具有广泛的底物范围。
Metal-Free sp<sup>2</sup>-C–H Borylation as a Common Reactivity Pattern of Frustrated 2-Aminophenylboranes
olefinic C-H bonds with 2-aminophenylboranes. Computational and experimentalstudies reveal that the metal-free C-H insertion proceeds via a frustrated Lewis pair mechanism involving heterolytic splitting of the C-H bond by cooperative action of the amine and boryl groups. The adapted geometry of the reactive B and N centers results in an unprecedentently low kinetic barrier for both insertion into the