Bifunctional Phosphine Ligand Enabled Gold‐Catalyzed Alkynamide Cycloisomerization: Access to Electron‐Rich 2‐Aminofurans and Their Diels–Alder Adducts
Bifunctional Phosphine Ligand Enabled Gold‐Catalyzed Alkynamide Cycloisomerization: Access to Electron‐Rich 2‐Aminofurans and Their Diels–Alder Adducts
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DOI：
10.1002/ange.201908598
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发表时间：
2019-09
影响因子：
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通讯作者：
X. Li;Xu Ma;Zhixun Wang;P. Liu;Liming Zhang
中科院分区：
文献类型：
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作者：
X. Li;Xu Ma;Zhixun Wang;P. Liu;Liming Zhang
通过使用远端叔氨基功能化的联苯-2-基膦作为配体，容易获得的乙基酰胺直接转化为2-氨基呋喃，没有任何吸电子，因此失活/稳定取代基。这些高富电子呋喃很少被制备出来，更不用说应用于合成了，因为呋喃环的高反应性和低稳定性与它们极其富电子的性质有关。在这项工作中，这些反应性呋喃顺利地进行原位分子间Diels-Alder反应，以提供高功能化/取代苯胺产物或分子内产物，以大多数良好至优异的收率提供咔唑-4-羧酸盐。这项工作为这类很少被研究的富电子呋喃提供了一个普遍和方便的途径，并将为它们的应用开辟令人兴奋的机会。多好的配体啊。利用专为金催化设计的双功能配体，乙炔酰胺在一步内高效地转化为2-氨基呋喃。这些呋喃的高富电子性质赋予它们特殊的合成价值，但很难通过其他方式获得。zhang@chem.ucsb.edu，网站：https://labs.chem.ucsb.edu/zhang/liming/。†这些作者同样贡献了本文的支持信息，通过文档末尾的链接给出。HHS公共访问作者手稿新化学国际教育英语。作者的手稿;11月25日在PMC 2020上市。最终编辑版本为：angnew Chem Int Ed english . 2019年11月25日；58(48): 17180 - 17184。doi: 10.1002 / anie.201908598。一个作家的手稿
By using biphenyl-2-ylphosphines functionalized with a remote tertiary amino group as ligand, readily available acetylenic amides are directly converted into 2-aminofurans devoid of any electron-withdrawing and hence deactivating/stabilizing substituents. These highly electron-rich furans have rarely been prepared, let alone being applied in synthesis, due to the high reactivities and low stabilities associated with their exceedingly electron-rich nature of the furan ring. In this work, these reactive furans undergo smoothly in-situ intermolecular Diels-Alder reactions to deliver highly functionalized/substituted aniline products or intramolecular ones to furnish carbazole-4-carboxylates in mostly good to excellent yields. This work offers a general and expedient access to this class of rarely studies electron-rich furans and shall open exciting opportunities for their applications. Graphical Abstract What a ligand. With bifunctional ligands specifically designed for gold catalysis, acetylenic amides are transformed into 2-aminofurans in a single step efficiently. The highly electron-rich nature of these furans bestows them exceptional synthetic values but difficult to access in other means. zhang@chem.ucsb.edu, Website: https://labs.chem.ucsb.edu/zhang/liming/. †These authors contributed equally Supporting information for this article is given via a link at the end of the document. HHS Public Access Author manuscript Angew Chem Int Ed Engl. Author manuscript; available in PMC 2020 November 25. Published in final edited form as: Angew Chem Int Ed Engl. 2019 November 25; 58(48): 17180–17184. doi:10.1002/anie.201908598. A uhor M anscript