A tandem highly stereoselective FeCl3-promoted synthesis of a bisindoline: synthetic utility of radical cations in heterocyclic construction
摘要:
dA conceptually distinctive stereoselective construction of the novel dimer, N-[N'-acetyl-7,7'-bis-(3,4-dimethoxy-phenyl)-7,8,7',8'-tetrahydro-N'H-[8,8']biindolyl-N-yl]-ethanone 25 (bisindoline) is described below. These structures, which include 7-(3,4-dimethoxyphenyl)-indoline 24 (veratryl indoline), were obtained by the tactical combination of palladium-catalysed coupling which produced 10-acetamido-3,4-dimethoxystilbene 9, followed by FeCl3 induced oxidative cyclization/dimerization. All new structures were fully characterized by 1- and 2D NMR spectroscopy, (proton, carbon-13, COSY, HMBC, HMQC) and mass spectrometry. Configurational assignments were further supported by semi-empirical AMI calculations. Mechanistic interpretations, consistent with our results, are discussed. (C) 2004 Elsevier Ltd. All rights reserved.
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.
Electrochemically Mediated Oxidative Transformations of Substituted 4-Methoxystilbenes: Effect of Ortho-Substituted Nucleophilic Groups
作者:Kam-Weng Chong、Fong-Jiao Hong、Noel F. Thomas、Yun-Yee Low、Toh-Seok Kam
DOI:10.1021/acs.joc.7b00753
日期:2017.6.16
undertaken to determine the influence of ortho′-substituted nucleophilicgroups (OH, NH2, or NHR) on the reactivity of anodically generated 4-methoxy- and 3,4-dimethoxystilbene cation radicals. The results showed that when ortho-substituted nucleophilicgroups such as OH and NHR are present in the other ring, both direct and crossover intramolecular cation–nucleophile reactions occur to give bisbenzofurans/bisindoles
The Subtle Co-catalytic Intervention of Benzophenone in Radical Cation Mediated Cyclization — An Improved Synthesis of 2-(3’,4’-Dimethoxyphenyl)indoline
作者:Noel Francis Thomas、Chin-Hui Kee、Azhar Ariffin、Khalijah Awang、Jean-Fr仕屍ic Faizal Weber、Chuan-Gee Lim、Mat Ropi Mukhtar、A. Hamid A. Hadi
DOI:10.3987/com-07-11280
日期:——
The addition of benzophenone to a FeCl 3 /CH 2 Cl 2 mixture in the presence of 3',4'-dimethoxy-2-acetamidostilbene 17 unexpectedly leads to a dramatic improvement in yield of the indoline 20 from 38% (previously reported by us) to 75.4%, after careful examination of a variety of reaction conditions. A catalytic cycle has been proposed that involves not only stilbene radical cations but also Fe 2+ promoted