Effective metal-free electrooxidative thiocyanation of anilines

Khodonov, V. M.; Kudinova, Anastasia S.; Kokorekin, Vladimir A.; Petrosyan, V. A.; Egorov, Mikhail P.

doi:10.1016/j.mencom.2022.01.030

Cited by 4 publications

(2 citation statements)

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“…About four main reaction pathways are reported for oxidative functionalization of arenes with C−S bond formation: attack of S‐centered radical on arene molecule, attack of S‐centered radical on arene radical ion, electrophilic attack of arene by RS−SR species generated in situ , and nucleophilic attack of arene radical cation by sulfur‐centered nucleophile [140] …”

Section: Radical Functionalization Of Heterocyclesmentioning

confidence: 99%

“…About four main reaction pathways are reported for oxidative functionalization of arenes with CÀ S bond formation: attack of S-centered radical on arene molecule, attack of S-centered radical on arene radical ion, electrophilic attack of arene by RSÀ SR species generated in situ, and nucleophilic attack of arene radical cation by sulfur-centered nucleophile. [140] To begin with, various maleimides 93 are sulfenylated with aromatic and aliphatic thiols in the presence of molecular iodine and NEt 3 . Introduction of MeSgroup into maleimides is performed using DMSO as the reagent under the action of only I 2 (Scheme 43).…”

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%

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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Electrooxidative Thiocyanation of Hydroxy‐ and Alkoxybenzenes

Moiseeva,

Sokolov,

Andreev

et al. 2024

Eur J Org Chem

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We developed an original method for thiocyanation of hydroxy‐ and alkoxy‐substituted benzenes (including naturally occurring compounds) using electrogenerated thiocyanogen, (SCN)₂. The presence of zinc chloride as a Lewis acid significantly enhances reaction efficiency by activating thiocyanogen. Cyclic voltammetry of the reactants and their combinations was employed to optimize reaction conditions and investigate the proposed mechanisms. This method demonstrated broad synthetic utility, leading to mono‐ and bis‐thiocyanated arenes and various heterocycles with yields 36–97 %. Notable products include the neuroprotective drug riluzole and precursors for the antiprotozoal drugs toltrazuril and ponazuril.

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