Electrochemical Oxidative C–H Thiocyanation or Selenocyanation of Imidazopyridines and Arenes

Cui, Ting; Xiao-feng, Zhang; Lin, Jun; Zhu, Zhimin; Liu, Ping; Sun, Peipei

doi:10.1055/a-1299-3009

Cited by 25 publications

(7 citation statements)

References 8 publications

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“…Some other fused heterocycles, such as thiazole derivatives, imidazo[1,2‐ a ]quinoline, and imidazo[1,2‐ a ]pyrazine, can also successfully participate in the developed transformation. The proposed electrochemical conditions are applied for selenocyanation with KSeCN [184] …”

Section: Radical Functionalization Of Heterocyclesmentioning

confidence: 99%

“…Electrochemical thiocyanation of imidazopyridines 144 and 146 with ammonium thiocyanate under constant current conditions also gives 3-substituted derivatives 145 and 147 (Scheme 62). [183,184] Undivided cell is used and MeCN is applied as the solvent. Some other fused heterocycles, such as thiazole derivatives, imidazo[1,2-a]quinoline, and imidazo[1,2-a]pyrazine, can also successfully participate in the developed transformation.…”

Section: Reactions With the Formation Of Cà S And Cà Se Bondsmentioning

confidence: 99%

“…The proposed electrochemical conditions are applied for selenocyanation with KSeCN. [184] Presumably, on the first step of electrochemical thiocyanation, SCN anion is anodically oxidized into the corresponding radical A (Scheme 63). After that, addition of SCN radical A to the preliminary formed on the anode imidazopyridine radical cation B (path A) takes place.…”

Section: Reactions With the Formation Of Cà S And Cà Se Bondsmentioning

confidence: 99%

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CH‐Functionalization of Heterocycles with the Formation of C−O, C−N, C−S/Se, and C−P Bonds by Intermolecular Addition of Heteroatom‐Centered Radicals

et al. 2023

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In the last decade, free radicals have found a wide application in functionalization of unsaturated compounds, such as alkenes, alkynes, and arenes, via the free-radical addition to carbon-carbon π-bonds. In these processes, intermolecular free-radical attack on the aromatic substrates represents a challenge due to relatively high resistance of aromatic π-system to addition reactions in comparison to alkene C=C bonds. The free-radical functionalization of heterocycles is especially interesting due to the diversity of their structures and chemical properties as well as their importance for medicinal chemistry, agrochemistry, and materials science. Addition of C-centered radicals to heterocycles is widely known as the Minisci-type reactions and well-reviewed. In this paper, we have summarized the main achievements in less explored group of processes: functionalization of heterocycles by intermolecular addition of heteroatom-centered radicals (O-, N-, S-/Se-, and P-radicals) with the emphasis on the papers published after 2010. Literature analysis revealed the strong trend towards the usage of electrochemistry and photoredox-catal-ysis for the generation of free radicals in recent years. The remaining fundamental problem in this field is the lack of strong experimental support for the proposed mechanisms and frequent existence of several plausible reaction pathways. The progress in mechanistic studies can significantly improve the prediction of optimal reaction conditions depending on the substrates structure. 1. Introduction 2. Radical Functionalization of Heterocycles 2.1. Reactions with the Formation of CÀ O Bonds 2.2. Reactions with the Formation of CÀ N Bonds 2.3. Reactions with the Formation of CÀ S and CÀ Se Bonds 2.4. Reactions with the Formation of CÀ P Bonds 3. Conclusions

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Section: Radical Functionalization Of Heterocyclesmentioning

confidence: 99%

Section: Reactions With the Formation Of Cà S And Cà Se Bondsmentioning

confidence: 99%

Section: Reactions With the Formation Of Cà S And Cà Se Bondsmentioning

confidence: 99%

See 1 more Smart Citation

CH‐Functionalization of Heterocycles with the Formation of C−O, C−N, C−S/Se, and C−P Bonds by Intermolecular Addition of Heteroatom‐Centered Radicals

et al. 2023

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“…59,[71][72][73] Electrochemical thiocyanation of C-H bonds has also made some progress, 74 especially in anodic thiocyanation of unsaturated or aromatic compounds. 57,[75][76][77][78][79][80][81][82] The few known examples of the electrochemical thiocyanation of carbonyl compounds are based on the in situ formation of α-halo ketones as the key intermediates followed by nucleophilic substitution of halogens with SCN − (Scheme 1, b). 80,83 Herein, we disclose the direct electrochemical thiocyanation of 1,3-dicarbonyl compounds in an undivided electrochemical cell via thiocyanogen generation without halogencontaining electrolytes (Scheme 1, c).…”

Section: Introductionmentioning

confidence: 99%

“…59,71–73 Electrochemical thiocyanation of C–H bonds has also made some progress, 74 especially in anodic thiocyanation of unsaturated or aromatic compounds. 57,75–82 The few known examples of the electrochemical thiocyanation of carbonyl compounds are based on the in situ formation of α-halo ketones as the key intermediates followed by nucleophilic substitution of halogens with SCN − (Scheme 1, b). 80,83…”

Section: Introductionmentioning

confidence: 99%

An environmentally benign way to synthesize 2-thiocyano-1,3-dicarbonyl compounds with high antifungal activity: a key role of solvent

et al. 2023

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Electrochemical Functionalization of Imidazopyridine and Indazole: An Overview

Ghosh¹,

Ghosh

Hajra

2021

Adv Synth Catal

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Electrochemical synthesis offers a mild, simple, and efficient tool for the preparation of interesting and useful molecules, thus eluding severe chemical oxidizing and reducing agents used in conventional synthetic methods. In particular, electrochemical C−H activation is expected to play an important role in the direct functionalization of heterocyclic compounds. Over the past few decades, the research interest in imidazopyridine and indazole has increased significantly due to their multipurpose uses in medicinal and industrial chemistry. Therefore, structural modification of these heterocycles using electro‐oxidation has become one of the important research topics among synthetic organic chemistry in recent time. This review provides a comprehensive discussion of electrochemical functionalization of indazoles and imidazopyridines published so far. A summary of the current challenges and the future direction for the development of efficient and green electrochemical methods for functionalization of these heterocycles is also presented.

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Electrochemical Oxidative C–H Thiocyanation or Selenocyanation of Imidazopyridines and Arenes

Cited by 25 publications

References 8 publications

CH‐Functionalization of Heterocycles with the Formation of C−O, C−N, C−S/Se, and C−P Bonds by Intermolecular Addition of Heteroatom‐Centered Radicals

CH‐Functionalization of Heterocycles with the Formation of C−O, C−N, C−S/Se, and C−P Bonds by Intermolecular Addition of Heteroatom‐Centered Radicals

An environmentally benign way to synthesize 2-thiocyano-1,3-dicarbonyl compounds with high antifungal activity: a key role of solvent

Electrochemical Functionalization of Imidazopyridine and Indazole: An Overview

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