Transition‐Metal‐Free Direct Trifluoromethylation and Perfluoroalkylation of Imidazopyridines under Mild Conditions

Han, Shuaijun; Gao, Xianying; Wu, Qingyan; Li, Jingya; Zou, Dapeng; Wu, Yangjie; Wu, Yusheng

doi:10.1002/adsc.201801541

Cited by 51 publications

(26 citation statements)

References 49 publications

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“…[82] Likewise, transition-metal-free CÀ H trifluoromethylation of imidazo[1,2-a]pyridine derivatives (278) with a combination of TMSCF 3 and PhI(OAc) 2 was disclosed (Scheme 55). [83] This protocol was also applied to the direct CÀ H perfluoroalkylation of imidazopyridines using TMSC n F 2n + 1 (n = 2, 3)/PhI (OAc) 2 . Consequently, a variety of useful perfluoroalkylated imidazo[1,2-a]pyridines (279) were obtained in moderate to good yields.…”

Section: Trifluoromethylation and Perfluoroalkylation Of Electron-ricmentioning

confidence: 99%

“…A tentative reaction mechanism for this CÀ H trifluoromethylation was suggested in Scheme 55. [83] Initially, hypervalent iodine(III) 216 is formed from TMSCF 3 /PhI(OAc) 2 in the presence of CsF, and undergoes homolysis to generate radical 217 and * CF 3 radical. Then, the * CF 3 radical reacts with 2phenylimidazo[1,2-a] pyridine (278 a) to produce a radical intermediate 280, which is converted to a cation intermediate 281 through a single electron transfer (SET).…”

Section: Trifluoromethylation and Perfluoroalkylation Of Electron-ricmentioning

confidence: 99%

“…Likewise, transition‐metal‐free C−H trifluoromethylation of imidazo[1,2‐a]pyridine derivatives ( 278 ) with a combination of TMSCF 3 and PhI(OAc) 2 was disclosed (Scheme ) . This protocol was also applied to the direct C−H perfluoroalkylation of imidazopyridines using TMSC n F 2n+1 (n=2, 3)/PhI(OAc) 2 .…”

Section: Trifluoromethylation and Perfluoroalkylation Initiated By Hymentioning

confidence: 99%

“…Advantages of this method included easy operation, high‐efficiency, mild conditions, good functional group tolerance and wide substrate scope. A tentative reaction mechanism for this C−H trifluoromethylation was suggested in Scheme . Initially, hypervalent iodine(III) 216 is formed from TMSCF 3 /PhI(OAc) 2 in the presence of CsF, and undergoes homolysis to generate radical 217 and .…”

Section: Trifluoromethylation and Perfluoroalkylation Initiated By Hymentioning

confidence: 99%

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Fluorination and Fluoroalkylation Reactions Mediated by Hypervalent Iodine Reagents

Han

Zhang

2020

Adv Synth Catal

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This review summarizes the progress in the fluorination and fluoroalkylation of electron-rich systems with diverse fluorine (F) and fluoroalkyl (R fn) reagents employing hypervalent iodine compounds as initiators in the last few decades. Because of the strong electrophilicity, high oxidizing properties, low toxicity, air and moisture stability, ready availability, ease of handling, and mild reaction conditions, the hypervalent iodine reagents have been widely utilized in modern organic chemistry. In particular, the use of hypervalent iodine reagents to initiate the CÀ F and CÀ R fn (R fn =CF 2 H, CF 3 , perfluoroalkyl, OCH 2 CF 3 , SCF 3 , SeCF 3 and etc) bond formation has been increasingly developed. In these reactions, hypervalent iodine compounds behave as powerful oxidants or electrophiles and activate the fluorination/fluoroalkylation reagents, the transitionmetal catalysts, or the substrates to in situ form electrophilic or radical intermediates, which subsequently participate in fluorination, difluoromethylation, trifluoromethylation, perfluoroalkylation, trifluoroethoxylation, fluoroalkylthiolation, trifluoromethylselenolation and others under mild conditions. Although great achievements have been made in this area, they are just the initial phase and still require a wide scope for improvement. It is anticipated that this review will draw much attention from the organic chemistry community and inspire more contributions in the development of new hyper-valent-iodine-mediated fluorination and fluoroalkylation reactions.

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Section: Trifluoromethylation and Perfluoroalkylation Of Electron-ricmentioning

confidence: 99%

Section: Trifluoromethylation and Perfluoroalkylation Of Electron-ricmentioning

confidence: 99%

Section: Trifluoromethylation and Perfluoroalkylation Initiated By Hymentioning

confidence: 99%

Section: Trifluoromethylation and Perfluoroalkylation Initiated By Hymentioning

confidence: 99%

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Fluorination and Fluoroalkylation Reactions Mediated by Hypervalent Iodine Reagents

Han

Zhang

2020

Adv Synth Catal

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“…Recently, Wu et al investigated a phenyliodine (III) diacetate (PIDA)-mediated trifluoromethylation and perfluoroalkylation of imidazoheterocycles with Ruppert-Prakash reagent (TMSCF 3 ) using CsF as base in acetonitrile (Scheme 12). [29] Various imidazoheterocycles (1--4) bearing different functional groups reacted well with a set of TMSCF 3 or TMSC 2 F 5 or TMSC 3 F 7 (TMSC n F 2n + 1 ; n = 1, 2, 3; 22) and produced the respective fluoroalkylated products 21 in 28-76% yields. TEMPO-CF 3 adduct was detected in GC-MS analysis of the reaction and thus, a radicalmediated mechanism was proposed.…”

Section: C3-fluoroalkylationmentioning

confidence: 99%

Recent Advances in Radical C−H Bond Functionalization of Imidazoheterocycles

et al. 2020

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Direct CÀ H bond functionalization through radical pathway has emerged as a powerful and ideal strategy for the synthesis of organic compounds. This review provides an overview of recent developments in radical CÀ H functionalization of imidazoheterocycles such as imidazo[1,2-a] pyridine, benzo[d]imidazo[2,1-b]thiazole, imidazo [2,1-b]thiazole, imidazo[1,2-a]pyrimidine, imidazo [2,1-a]isoquinoline, imidazo[1,2-a]pyrazine and imidazo[1,2-a]quinoline using organic peroxides, photo/electric-induced protocols, iodine-based reagents, first-row transition metal catalysts (Fe, Mn, Ni and Cu) and inorganic oxidants/or

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Direct CH Difluoroalkylation and Perfluoroalkylation of Heteroarenes

Fruit¹

2022

Handbook of CH-Functionalization

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This article summarizes the main recent achievements reported in transition metal‐catalyzed and metal‐free CH difluoromethylation and perfluoroalkylation using various fluoroalkyl‐coupling partners over the past decade, for constructing high‐valuable fluoro‐containing heteroarenes. This resume is mainly categorized based on different catalytic systems for each fluoroalkylation reaction. Difluoroalkylation that involves a metal‐catalyzed or a visible‐light‐induced reaction will be addressed first. Following this, the direct perfluoroalkylation of CH bonds under various reaction conditions will be covered. The overall aim is to paint a picture of the state of the art in difluoro‐ and perfluoroalkylation chemistry for medicinal chemists and point out how the recent innovative strategies have been able to positively affect the synthesis of new bioactive compounds.

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Transition‐Metal‐Free Direct Trifluoromethylation and Perfluoroalkylation of Imidazopyridines under Mild Conditions

Cited by 51 publications

References 49 publications

Fluorination and Fluoroalkylation Reactions Mediated by Hypervalent Iodine Reagents

Fluorination and Fluoroalkylation Reactions Mediated by Hypervalent Iodine Reagents

Recent Advances in Radical C−H Bond Functionalization of Imidazoheterocycles

Direct CH Difluoroalkylation and Perfluoroalkylation of Heteroarenes

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