Synthesis of 2,3-Disubstituted Benzo[<i>b</i>]thiophenes via Palladium-Catalyzed Coupling and Electrophilic Cyclization of Terminal Acetylenes
作者:Dawei Yue、Richard C. Larock
DOI:10.1021/jo011016q
日期:2002.3.1
alkyl-substituted terminal acetylenes undergo this coupling and cyclization to produce excellent yields of benzo[b]thiophenes. (Trimethylsilyl)acetylene also undergoes this coupling/cyclization process with I(2), NBS, and the sulfur and selenium electrophiles to afford the corresponding 2-(trimethylsilyl)benzo[b]thiophenes. However, cyclization of the silyl-containing thioanisole using Br(2) affords
Synthesis of Benzo[<i>b</i>]thiophenes via Electrophilic Sulfur Mediated Cyclization of Alkynylthioanisoles
作者:Zahra Alikhani、Alyssa G. Albertson、Christopher A. Walter、Prerna J. Masih、Tanay Kesharwani
DOI:10.1021/acs.joc.1c02606
日期:2022.5.6
A stable dimethyl(thiodimethyl)sulfonium tetrafluoroborate salt was employed for the electrophilic cyclization reaction of o-alkynyl thioanisoles for the synthesis of 2,3-disubstituted benzo[b]thiophenes. The reaction described herein works well with various substituted alkynes in excellent yields, and a valuable thiomethyl group was introduced with ease. The reaction utilizes moderate reaction conditions
一种稳定的二甲基(硫代二甲基)锍四氟硼酸盐用于邻炔基硫代苯甲醚的亲电环化反应,用于合成 2,3-二取代苯并[ b ]噻吩。本文描述的反应以优异的收率与各种取代的炔烃一起工作,并且很容易引入有价值的硫甲基。该反应利用温和的反应条件和环境温度,同时耐受各种功能。为了阐明机理,证明了使用二甲基(硫代二甲基)锍四氟硼酸盐与二苯乙炔的亲电加成反应。
Environmentally benign process for the synthesis of 2,3-disubstituted benzo[b]thiophenes using electrophilic cyclization
作者:Seoyoung Kim、Nikesh Dahal、Tanay Kesharwani
DOI:10.1016/j.tetlet.2013.05.139
日期:2013.8
We have developed a greener process for the synthesis of 2,3-disubstituted benzo[b]thiophenes using electrophilic cyclization as a key step. Our method not only employs an environmentally friendly solvent ethanol, but also utilizes safe and inexpensive inorganic reagents to furnish the desired products in high yields under mild reaction conditions. In addition to iodo- and bromocyclization, chlorocylization was also successfully accomplished. (c) 2013 Elsevier Ltd. All rights reserved.
Green synthesis of benzo[b]thiophenes via iron(III) mediated 5-endo-dig iodocyclization of 2-alkynylthioanisoles
作者:Tanay Kesharwani、Cory T. Kornman、Amanda L. Tonnaer、Andrew D. Royappa
DOI:10.1016/j.tetlet.2015.12.037
日期:2016.1
A reaction of iron(III) chloride with sodium iodide was used to generate iodine for an innovative take on electrophilic cyclization. With ethanol as solvent, the reaction was observed to provide ideal conditions for iodocyclization of 2-alkynylthioanisoles. The fundamental step allows formation of iodine which becomes free to undergo reaction with the starting alkyne to yield the cyclized product. Implementing environmentally benign and simple chemistry, 2-iodosubstituted benzo[b]thiophenes were synthesized in high yields to produce an interesting display of useful molecules. (C) 2015 Elsevier Ltd. All rights reserved.
Sodium halides as the source of electrophilic halogens in green synthesis of 3-halo- and 3, n -dihalobenzo[ b ]thiophenes
A convenient methodology for the synthesis of mono- and di-halogenated benzo[b]thiophenes is described herein, which utilizes copper(II) sulfate pentahydrate and various sodium halides in the presence of substituted 2-alkynylthioanisoles. The proposed method is facile, uses ethanol as a green solvent, and results in uniquely substituted benzo[b]thiophene structures with isolated yields up to 96%. The