Scope and Mechanism of the Ruthenium-Catalyzed sp3 C–H Coupling Reaction of 2-Alkylindoles with Enones for the Synthesis of Carbazole Derivatives

IF 2.5 3区 化学 Q2 CHEMISTRY, INORGANIC & NUCLEAR
Krishna Prasad Gnyawali, Mina Son, Donghun Hwang, Nuwan Pannilawithana, Mu-Hyun Baik* and Chae S. Yi*, 
{"title":"Scope and Mechanism of the Ruthenium-Catalyzed sp3 C–H Coupling Reaction of 2-Alkylindoles with Enones for the Synthesis of Carbazole Derivatives","authors":"Krishna Prasad Gnyawali,&nbsp;Mina Son,&nbsp;Donghun Hwang,&nbsp;Nuwan Pannilawithana,&nbsp;Mu-Hyun Baik* and Chae S. Yi*,&nbsp;","doi":"10.1021/acs.organomet.4c0047010.1021/acs.organomet.4c00470","DOIUrl":null,"url":null,"abstract":"<p >The catalytic system consisting of a cationic Ru–H complex <b>1</b> and 3,4,5,6-tetrachloro-1,2-benzoquinone (<b>L1</b>) was found to be highly effective for the dehydrative sp<sup>3</sup> C–H coupling reaction of 2-alkyl substituted indoles with enones to form 2,4-disubstituted carbazole products. The analogous coupling reaction of 2-alkylindoles with linear enones bearing the cyclic olefinic group afforded tetracyclic carbazole products. A normal deuterium kinetic isotope effect was measured from the coupling reaction of 1,2-dimethylindole versus 1-methyl-2-(methyl-<i>d</i><sub>3</sub>)indole with (<i>E</i>)-3-penten-2-one (<i>k</i><sub>H</sub>/<i>k</i><sub>D</sub> = 2.5). The Hammett plot was constructed from the reaction of <i>para</i>-substituted indoles 5-X-1,2-dimethylindole (X = OMe, Me, H, F, and Cl) with 4-phenyl-3-buten-2-one (ρ = −1.6 ± 0.2). The density functional theory (DFT) calculations were performed to obtain a complete energy profile for the coupling reaction. The combined experimental and DFT computational data revealed a detailed mechanistic path that features an initial coupling of indole and enone substrates, the turnover-limiting heterolytic sp<sup>3</sup> C–H activation step, and the subsequent cyclization and dehydration steps. The catalytic method provides an efficient synthesis of carbazole derivatives from the dehydrative sp<sup>3</sup> C–H coupling reaction of readily available indole with enone substrates without employing any reactive reagents or forming wasteful byproducts.</p>","PeriodicalId":56,"journal":{"name":"Organometallics","volume":"44 1","pages":"325–334 325–334"},"PeriodicalIF":2.5000,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Organometallics","FirstCategoryId":"92","ListUrlMain":"https://pubs.acs.org/doi/10.1021/acs.organomet.4c00470","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
引用次数: 0

Abstract

The catalytic system consisting of a cationic Ru–H complex 1 and 3,4,5,6-tetrachloro-1,2-benzoquinone (L1) was found to be highly effective for the dehydrative sp3 C–H coupling reaction of 2-alkyl substituted indoles with enones to form 2,4-disubstituted carbazole products. The analogous coupling reaction of 2-alkylindoles with linear enones bearing the cyclic olefinic group afforded tetracyclic carbazole products. A normal deuterium kinetic isotope effect was measured from the coupling reaction of 1,2-dimethylindole versus 1-methyl-2-(methyl-d3)indole with (E)-3-penten-2-one (kH/kD = 2.5). The Hammett plot was constructed from the reaction of para-substituted indoles 5-X-1,2-dimethylindole (X = OMe, Me, H, F, and Cl) with 4-phenyl-3-buten-2-one (ρ = −1.6 ± 0.2). The density functional theory (DFT) calculations were performed to obtain a complete energy profile for the coupling reaction. The combined experimental and DFT computational data revealed a detailed mechanistic path that features an initial coupling of indole and enone substrates, the turnover-limiting heterolytic sp3 C–H activation step, and the subsequent cyclization and dehydration steps. The catalytic method provides an efficient synthesis of carbazole derivatives from the dehydrative sp3 C–H coupling reaction of readily available indole with enone substrates without employing any reactive reagents or forming wasteful byproducts.

Abstract Image

求助全文
约1分钟内获得全文 求助全文
来源期刊
Organometallics
Organometallics 化学-无机化学与核化学
CiteScore
5.60
自引率
7.10%
发文量
382
审稿时长
1.7 months
期刊介绍: Organometallics is the flagship journal of organometallic chemistry and records progress in one of the most active fields of science, bridging organic and inorganic chemistry. The journal publishes Articles, Communications, Reviews, and Tutorials (instructional overviews) that depict research on the synthesis, structure, bonding, chemical reactivity, and reaction mechanisms for a variety of applications, including catalyst design and catalytic processes; main-group, transition-metal, and lanthanide and actinide metal chemistry; synthetic aspects of polymer science and materials science; and bioorganometallic chemistry.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信