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。
Electrochemical Dearomative 2,3-Difunctionalization of Indoles
作者:Ju Wu、Yingchao Dou、Régis Guillot、Cyrille Kouklovsky、Guillaume Vincent
DOI:10.1021/jacs.8b13371
日期:2019.2.20
oxidative dearomatization of indoles leading to 2,3-dialkoxy or 2,3-diazido indolines under undivided conditions at a constant current. This operationally simple electro-oxidative procedure avoids the use of an external oxidant and displays excellent functional group compatibility. The formation of the two C-O or C-N bonds is believed to arise from the oxidation of the indoles into radical cation intermediates
我们报告了使用电化学对吲哚进行直接氧化脱芳构化,在恒定电流下在未分开的条件下产生 2,3-二烷氧基或 2,3-二叠氮二氢吲哚。这种操作简单的电氧化程序避免了使用外部氧化剂并显示出优异的官能团兼容性。两个 CO 或 CN 键的形成被认为是由吲哚氧化成自由基阳离子中间体引起的。
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.
aqueous medium via 5-exo-trig cyclization reaction. The scope of the reaction was extended to intermolecular Csp2-Csp2 and Csp2-N bond forming reactions in water. Systematic investigations revealed that altering hydrophobicity of surfactant influences the yield of both CC and CN bond forming reactions in water.
Molybdenum-Catalyzed α-Hydrostannations of Propargylamines as the Key Step in the Synthesis of N-Heterocycles
作者:Hechun Lin、Uli Kazmaier
DOI:10.1002/ejoc.200801157
日期:2009.3
The Mo-catalyzed hydrostannation of propargylic amines and amides gave rise to functionalized vinylstannanes in good yield. The α-stannylated products were formed preferentially, which are interesting synthetic building blocks. If halogenated aromatic amines were subjected to this protocol, the products obtained could be converted into indole and isoquinoline derivatives through intramolecular Stille
Dearomative Diallylation of <i>N</i>-Acylindoles Mediated by FeCl<sub>3</sub>
作者:Ju Wu、Raj Kumar Nandi、Régis Guillot、Cyrille Kouklovsky、Guillaume Vincent
DOI:10.1021/acs.orglett.8b00361
日期:2018.4.6
Three-dimensional indolines possessing two contiguous-stereogenic centers were obtained stereoselectively via the FeCl3-mediated dearomative introduction of two allyl groups to N-acylindoles with allyltrimethylsilane. Synthetic transformations allowed obtention of trans-tetrahydrocarbazoles and an aza[4.4.3]propellane scaffold by RCM. Selective hydration of one of the allyl groups was also achieved.