已开发出一种用于将多种简单和杂环芳烃与芳基碘化物、溴化物和氯化物进行分子内直接芳基化的催化剂。这些反应以极好的收率发生并且具有高度选择性。对芳基碘化物底物的研究表明,由于碘化物在反应介质中的积累,会发生催化剂中毒。这可以通过添加银盐来克服,银盐也允许这些反应在较低温度下发生。该方法的效用通过咔唑天然产物的快速合成和通过直接芳基化产物的开环反应合成空间位阻四邻位取代的联芳基来说明。机理研究提供了对催化剂的深入了解 s 作用模式并显示在钯催化的简单芳烃的直接芳基化中存在动力学上显着的 CH 键裂解。从这些研究中获得的知识导致了以前无法获得的芳烃的新分子间芳基化反应的发展,为其他新的直接芳基化过程的发展打开了大门。
Ultrasound-promoted intramolecular direct arylation in a capillary flow microreactor
作者:Lei Zhang、Mei Geng、Peng Teng、Dan Zhao、Xi Lu、Jian-Xin Li
DOI:10.1016/j.ultsonch.2011.07.008
日期:2012.3
An intramoleculardirectarylation of various aryl bromides was performed using ultrasonic irradiation and a continuous flow capillary microreactor. The present procedure provided a higher functional group tolerance, ligand-free, milder reaction conditions and a shorter reaction time for the directarylation compared with the conventional methods. The ultrasonic irritation not only greatly promoted
Aryl–aryl cross-coupling reactions without reagents or catalysts: photocyclization of <i>ortho</i>-iodoaryl ethers and related compounds <i>via</i> triplet aryl cation intermediates
作者:Wei Sun、Luke Wilding-Steele、Richard C. D. Brown、David C. Harrowven
DOI:10.1039/d3cc03271j
日期:——
Cyclisations of benzyl ortho-iodoaryl ethers to benzo[c]chromenes can be effected without reagents or catalysts by irradiation with UVC under flow. Reactions proceed via triplet aryl cation generation, 5-exo and 3-exo-cyclisations, and rearomatisation. They have wide scope, are easy to effect and extend to a myriad of related ring systems.
苄基邻碘芳基醚环化成苯并[ c ]色烯可以在没有试剂或催化剂的情况下通过在流动下用UVC照射来实现。反应通过三线态芳基阳离子生成、5-外型和3-外型环化以及重新芳构化进行。它们的范围很广,很容易实现并扩展到无数相关的环系统。
DERLIN, J. P., CAN. J. CHEM. <CJCH-A6>, 197, 53, NO 3, 343-349