Electro-/photocatalytic alkene-derived radical cation chemistry: recent advances in synthetic applications

Chemical Society Reviews, Journal Year: 2022, Volume and Issue: 51(16), P. 7206 - 7237

Published: Jan. 1, 2022

This review covers the recent progress in electro-/photo-catalytic alkene-derived radical cation chemistry for organic synthesis, including synthetic strategies, plausible mechanisms and further research outlook.

Language: Английский

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Unraveling the Structure and Reactivity Patterns of the Indole Radical Cation in Regioselective Electrochemical Oxidative Annulations

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(5), P. 3175 - 3186

Published: Jan. 27, 2023

Oxidation-induced strategy for inert chemical bond activation through highly active radical cation intermediate has exhibited unique reactivity. Understanding the structure and reactivity patterns of intermediates is crucial in mechanistic study will be beneficial developing new reactions. In this work, properties indole cations have been revealed using time-resolved transient absorption spectroscopy, situ electrochemical UV–vis, electron paramagnetic resonance (EPR) technique. Density functional theory (DFT) calculations were used to explain predict regioselectivity several oxidative annulations. Based on understanding inherent cations, two different regioselective annulations indoles successfully developed under oxidation conditions. Varieties furo[2,3-b]indolines furo[3,2-b]indolines synthesized good yields with high regioselectivities. Our insights into promote further development oxidation-induced functionalizations.

Language: Английский

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Electroreduction Enables Regioselective 1,2‐Diarylation of Alkenes with Two Electrophiles

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(17)

Published: Feb. 24, 2023

Precisely introducing two similar functional groups into bulk chemical alkenes represents a formidable route to complex molecules. Especially, the selective activation of electrophiles is in crucial demand, yet challenging for cross-electrophile-coupling. Herein, we demonstrate redox-mediated electrolysis, which aryl nitriles are both radical precursors and redox-mediators, enables an intermolecular alkene 1,2-diarylation with remarkable regioselectivity, thereby avoiding involvement transition-metal catalysts. This transformation utilizes cyanoarene anions activating various halides (including iodides, bromides, even chlorides) affords adducts up 83 % yield >20 : 1 regioselectivity more than 80 examples, providing feasible approach bibenzyl derivatives.

Language: Английский

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Radical 1,2-Nitrogen Migration Cascades of β-Bromo α-Amino Acid Esters to Access β-Amino Acid Motifs Enabled by Cooperative Ni/Diboron Catalysis

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(8), P. 5491 - 5502

Published: March 28, 2024

Amino acid esters serve as crucial intermediates in protein synthesis and common structural elements biologically active natural compounds. Herein, we present an efficient radical cascade reaction involving 1,2-nitrogen migration C(sp2)–H intramolecular cyclization, enabling access to a diverse array of β-amino motifs. Upon cooperative Ni/diboron catalysis, π-system-independent 1,2-N-shift β-bromo α-amino is achieved, which allows the formation two new bonds, including C(sp3)–C(sp2) bond C(sp3)–N bond. The exhibits extensive substrate compatibility high diastereoselectivity proceeds without need for oxidants, toxic initiators, and/or elevated temperatures. It has been observed that diboron compounds both activating reagent inert C–N cleavage/migration reductant Ni catalytic cycle. This sheds light on remote N-functionalities π-systems. cascades followed by intermolecular halogenation or selenation are also demonstrated.

Language: Английский

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Electrochemical Radical Silyl‐Oxygenation of Activated Alkenes

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(16), P. 8744 - 8749

Published: Feb. 6, 2021

Abstract An efficient electrochemical radical silyl‐oxygenation of electron‐deficient alkenes is demonstrated, which gives access to a variety new highly functionalized silicon‐containing molecules, including β‐silyl‐cyanohydrin derivatives in good yields with excellent chemo‐ and regio‐selectivity. This silylation process conducts under mild conditions without the use transition metal catalyst or chemical oxidant exhibits wide scope substrate silanes high functional‐group tolerance. The ability silyl radicals using Si−H activation offers perspectives for synthesis valuable organosilicon compounds sustainable green manner.

Language: Английский

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Electrochemical Desaturative β‐Acylation of Cyclic N‐Aryl Amines

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 61(6)

Published: Dec. 8, 2021

Abstract Herein, we disclose a straightforward, robust, and simple route to access β‐substituted desaturated cyclic amines via an electrochemically driven desaturative β‐functionalization of amines. This transformation is based on multiple single‐electron oxidation processes using catalytic amounts ferrocene. The reaction proceeds in the absence stoichiometric electrolyte under mild conditions, affording desired products with high chemo‐ regioselectivity. was tolerant broad range substrates also enables late‐stage β‐C(sp 3 )−H acylation potentially valuable products. Preliminary mechanistic studies voltammetry reveal key role ferrocene as redox mediator reaction.

Language: Английский

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Unlocking the Friedel-Crafts arylation of primary aliphatic alcohols and epoxides driven by hexafluoroisopropanol

Chem, Journal Year: 2021, Volume and Issue: 7(12), P. 3425 - 3441

Published: Nov. 17, 2021

Alcohols and epoxides are arguably ideal electrophiles for the Friedel-Crafts alkylation, since they widely available, require no pre-activation, produce stoichiometric waste beyond water. However, neither primary aliphatic alcohols nor most classes of terminal compatible with existing intermolecular methodologies, sequential reactions starting from consequently remain underexplored. Here, we report that these limitations easily overcome using Brønsted acid catalysis in hexafluoroisopropanol (HFIP) as a solvent. Electron-poor aromatic undergo stereospecific arylation to give an alcohol which, depending on reaction conditions, can partake second nucleophilic substitution different arene one pot. Phenyl ethanols react through phenonium intermediate, whereas simple participate rare SN2 process, delivering linear products exclusively. This work provides alternative metal-catalyzed cross-couplings accessing important scaffolds, widening range applications reaction.

Language: Английский

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Site‐Selective Electrochemical C−H Carboxylation of Arenes with CO₂

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 62(3)

Published: Nov. 16, 2022

Herein, a direct, metal-free, and site-selective electrochemical C-H carboxylation of arenes by reductive activation using CO2 as the economic abundant carboxylic source was reported. The electrocarboxylation carried out in an operationally simple manner with high chemo- regioselectivity, setting stage for challenging unactivated (hetero)arenes. robust nature strategy reflected broad scope substrates excellent atom economy unique selectivity. Notably, direct selective various worked well this approach, including electron-deficient naphthalenes, pyridines, phenyl derivatives, substituted quinolines. method benefits from being externally catalyst-free, metal-free base-free, which makes it extremely attractive potential applications.

Language: Английский

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Intermolecular 1,2-Difunctionalization of Alkenes Enabled by Fluoroamide-Directed Remote Benzyl C(sp³)–H Functionalization

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 144(1), P. 339 - 348

Published: Dec. 22, 2021

A copper-catalyzed remote benzylic C-H functionalization strategy enabling 1,2-difunctionalization of alkenes with 2-methylbenzeneamides and nucleophiles, including alcohols, indoles, pyrroles, the intrinsic amino groups, is reported, which characterized by its redox-neutral conditions, exquisite site-selectivity, broad substrate scope, wide utilizations late-stage modifying bioactive molecules. This reaction proceeds through nitrogen-centered radical generation, hydrogen atom transfer, addition across alkenes, single-electron oxidation, carbocation electrophilic course cascades. While using external nucleophiles manipulates three-component alkene alkylalkoxylation alkyl-heteroarylation to access dialkyl ethers, 3-alkylindoles, 3-alkylpyrroles, omitting results in two-component alkylamidation ([5+2] annulation) benzo-[f][1,2]thiazepine 1,1-dioxides.

Language: Английский

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Recent progress on electrochemical synthesis involving carboxylic acids

Organic & Biomolecular Chemistry, Journal Year: 2021, Volume and Issue: 19(25), P. 5501 - 5520

Published: Jan. 1, 2021

Recent progress on sustainable electrochemical synthesis involving carboxylic acids was reviewed.

Language: Английский

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