Ring-Opening of Indoles: An Unconventional Route for the Transformation of Indoles to 1<i>H</i>-Pyrazoles Using Lewis Acid
作者:Subhankar Panda、Nirmalya Pradhan、Debasis Manna
DOI:10.1021/acscombsci.8b00071
日期:2018.10.8
unusual transformation of indoles to pyrazoles via an aromatic ring-opening strategy has been developed. The salient feature of this strategy involves the C2–N1 bond opening and concomitant cyclization reaction of the C2═C3 bond of the indole moiety with the tosylhydrazone, which proceeds under transition-metal and ligand free conditions. This ring-opening functionalization of indoles provides a wide scope
A Versatile Catalyst for Intermolecular Direct Arylation of Indoles with Benzoic Acids as Arylating Reagents
作者:Jun Zhou、Peng Hu、Min Zhang、Shijun Huang、Min Wang、Weiping Su
DOI:10.1002/chem.201000529
日期:2010.5.25
(Pd(TFA)2/Ag2CO3/propionic acid) both electron‐rich and ‐deficient benzoicacids serve as arylating reagents for the direct functionalization of a wide rage of indoles by a combination of decarboxylation and CH bond activation. Depending on the nature of the benzoicacids, the reaction occurs selectively at either the C2‐ or C3‐position of indoles, which may arise from two different catalytic pathways (see scheme;
耦合在一起:借助通用的催化剂体系(Pd(TFA)2 / Ag 2 CO 3 /丙酸),富电子和不足的苯甲酸都可以作为芳构化试剂,通过以下两种方法的结合直接将多种吲哚官能化脱羧和CH键活化。根据苯甲酸的性质,该反应选择性地发生在吲哚的C2或C3位置,这可能是由两种不同的催化途径引起的(请参阅方案; TFA =三氟乙酸盐)。
Direct Bis-Alkyl Thiolation for Indoles with Sulfinothioates under Pummerer-Type Conditions
作者:Peng Qi、Fang Sun、Ning Chen、Hongguang Du
DOI:10.1021/acs.joc.1c02502
日期:2022.1.21
applications. This approach enabled double C–H thiolation at the C2 and C3 of the indole in one pot. The mechanism studies suggested the thiolation was realized through the sulfoxonium salt rather than sulfenylcarboxylate.
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.
been functionalized using this property. Indole also forms indolium, which allows electrophilic addition in acidic conditions, but current examples have been limited to intramolecular reactions. C2 site-selective nucleophilic addition to indole derivatives using fluoroalcohol and a Lewisacid was developed.