Catalytic direct arylation with aryl chlorides, bromides, and iodides: Intramolecular studies leading to new intermolecular reactions
Catalytic direct arylation with aryl chlorides, bromides, and iodides: Intramolecular studies leading to new intermolecular reactions
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DOI：
10.1021/ja055819x
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发表时间：
2006-01-18
影响因子：
15
通讯作者：
Fagnou, K
中科院分区：
文献类型：
--
作者：
Campeau, LC;Parisien, M;Fagnou, K
已经开发了用于分子内直接芳基化的催化剂，该催化剂已开发出具有芳基碘化物，溴化物和氯化物的广泛范围的简单和杂环。这些反应以极好的产量出现，并且具有高度选择性。芳基碘化物底物的研究表明，由于反应培养基中碘化物的积累，催化剂中毒发生。可以通过添加银盐来克服这，这也允许这些反应在较低的温度下发生。该方法的效用是通过快速合成甲壳唑天然产物的效用，并通过直接芳基化产物的环室开环反应合成了宽带的四方 - 奥特拉 - 奥特拉（Tetra-Ortho）取代的双子体。机械研究为催化剂的作用方式提供了深入的了解，并显示了在钯催化的简单领域的直接芳基化中存在动力学显着的C-H键裂解。从这些研究中获得的知识导致了新的分子间芳基化反应与以前难以接近的领域的发展，为开发其他新的直接芳基化过程打开了大门。
A catalyst for the intramolecular direct arylation of a broad range of simple and heterocyclic arenes with aryl iodides, bromides, and chlorides has been developed. These reactions occur in excellent yield and are highly selective. Studies with aryl iodides substrates revealed that catalyst poisoning occurs due to the accumulation of iodide in the reaction media. This can be overcome by the addition of silver salts which also permits these reactions to occur at lower temperature. The utility of the methodology is illustrated by a rapid synthesis of a carbazole natural product and by the synthesis of sterically encumbered tetra-ortho-substituted biaryls via ring-opening reactions of the direct arylation products. Mechanistic investigations have provided insight into the catalyst's mode of action and show the presence of a kinetically significant C-H bond cleavage in palladium-catalyzed direct arylation of simple arenes. Knowledge garnered from these studies has led to the development of new intermolecular arylation reactions with previously inaccessible arenes, opening the door for the development of other new direct arylation processes.