para-Selective Arylation of Arenes: A Direct Route to Biaryls by Norbornene Relay Palladation
para-Selective Arylation of Arenes: A Direct Route to Biaryls by Norbornene Relay Palladation
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DOI：
10.1002/anie.202005664
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发表时间：
2020-09-09
影响因子：
16.6
通讯作者：
Maiti, Debabrata
中科院分区：
文献类型：
--
作者：
Dutta, Uttam;Porey, Sandip;Maiti, Debabrata
联芳基化合物是天然产物、生物活性成分和药物中极其重要的结构基元。通过区分远端芳烃C-H键的细微反应活性差异来选择合成联芳基是一项极具挑战性的工作。在这里，我们描述了一种对选择性的C-H芳基化反应，它是由氨基和降冰片烯作为瞬时介体的独特组合而实现的。在降冰片烯的存在下，直接间位C-H苍白反应发生单键继而苍白，随后磺酸盐、膦酸盐和含2，6-二取代模式的酚类化合物发生对C-H芳基化反应。该方案适用于缺电子的芳基碘化物。多取代芳烃和苯酚是通过产物的合成后修饰得到的。该方案允许通过顺序选择性末端C-H官能化来合成六取代苯。
Biaryl compounds are extremely important structural motifs in natural products, biologically active components and pharmaceuticals. Selective synthesis of biaryls by distinguishing the subtle reactivity difference of distal arene C-H bonds are significantly challenging. Herein, we describepara-selective C-H arylation, which is acheived by a unique combination of ameta-directing group and norbornene as a transient mediator. Upon directmeta-C-H palladation, one-bond relay palladation occurs in presence of norbornene and subsequentlypara-C-H arylation is achieved for sulfonates, phosphonates and phenols bearing 2,6-disubstitution patterns. The protocol is amenable to electron-deficient aryl iodides. Multisubstituted arenes and phenols are obtained by postsynthetic modification of the products. The protocol allows the synthesis of hexa-substituted benzene by sequential selective distal C-H functionalization.