Triflic Acid as an Efficient Brønsted Acid Promoter for the Umpolung of N-Ac Indoles in Hydroarylation Reactions
作者:Raj Kumar Nandi、Alejandro Perez-Luna、Didier Gori、Rodolphe Beaud、Régis Guillot、Cyrille Kouklovsky、Vincent Gandon、Guillaume Vincent
DOI:10.1002/adsc.201701074
日期:2018.1.4
We report that triflicacid, a strong Brønsted acid, is a very powerful alternative to FeCl3 to mediate the hydroarylation of N−Ac indoles, which delivers regioselectively 3‐arylindolines, 3,3‐spiroindolines or 2‐arylindolines. Mechanistic explorations point towards the existence of a highly electrophilic intermediate by simultaneous activation of the acetyl and of the C2=C3 bond by protons.
Direct Oxidative Coupling of<i>N</i>-Acetyl Indoles and Phenols for the Synthesis of Benzofuroindolines Related to Phalarine
作者:Terry Tomakinian、Régis Guillot、Cyrille Kouklovsky、Guillaume Vincent
DOI:10.1002/anie.201404055
日期:2014.10.27
by the biogenetic synthesis of benzofuroindoline‐containing natural products, we designed an oxidative coupling between phenol and N‐acetyl indoles. This straightforward and direct radical process, mediated by 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone and FeCl3 allowed the regioselective synthesis of benzofuro[3,2‐b]indolines, whose structure is found in the natural product phalarine.
inert chemical bond activation through highly active radicalcation intermediate has exhibited unique reactivity. Understanding the structure and reactivity patterns of radicalcation intermediates is crucial in the mechanistic study and will be beneficial for developing new reactions. In this work, the structure and properties of indole radicalcations have been revealed using time-resolved transient
通过高活性自由基阳离子中间体激活惰性化学键的氧化诱导策略表现出独特的反应性。了解自由基阳离子中间体的结构和反应模式在机理研究中至关重要,并将有利于开发新反应。在这项工作中,吲哚自由基阳离子的结构和性质已经通过时间分辨瞬态吸收光谱、原位电化学紫外-可见光和原位电化学电子顺磁共振(EPR)技术。密度泛函理论 (DFT) 计算用于解释和预测几种电化学氧化吲哚环化的区域选择性。基于对几种吲哚自由基阳离子固有特性的理解,在电化学氧化条件下成功开发了两种不同的吲哚区域选择性环化。各种呋喃并[2,3- b ]二氢吲哚和呋喃[3,2- b ]二氢吲哚以高产率和高区域选择性合成。我们对吲哚自由基阳离子的机理见解将促进氧化诱导的吲哚功能化的进一步发展。
Visible-light-driven [3 + 2] cyclization of phenols with indoles and olefins using recyclable Ag<sub>3</sub>PO<sub>4</sub> nanoparticles
作者:Lirong Guo、Guanjie Chen、Haibin Li、Chen-Ho Tung、Yifeng Wang
DOI:10.1039/d3gc02418k
日期:——
Ag3PO4 promotes the oxidative [3 + 2] annulation of phenols with styrenes and indoles for the syntheses of 2,3-dihydrobenzofurans and benzofuroindolines under visible-light irradiation. The approach is additive-free, mild, scalable, and, most importantly, Ag3PO4 recyclable. The mechanism involves the cross-coupling of stabilized phenol radical and styrene radical cation on the Ag3PO4 surfaces.
Ag 3 PO 4促进苯酚与苯乙烯和吲哚的氧化[3 + 2]环化,用于在可见光照射下合成2,3-二氢苯并呋喃和苯并呋喃二氢吲哚。该方法无添加剂、温和、可扩展,最重要的是,Ag 3 PO 4可回收。该机理涉及稳定的苯酚自由基和苯乙烯自由基阳离子在Ag 3 PO 4表面上的交叉偶联。
Iron-Mediated Domino Interrupted Iso-Nazarov/Dearomative (3 + 2)-Cycloaddition of Electrophilic Indoles
An efficient domino reaction combining different classes of pericyclic reactions leads to chiral complex polycyclic indoline-based architectures from achiral starting materials under mild conditions. This practical method is based on the ability of iron(III) chloride to promote both 4 pi electrocyclizations of 2,4-dienals and the C2-C3 umpolung of N-acetylindoles during the dearomative (3 + 2) cycloadditions.