Photochemical and Electrochemical Applications of Proton-Coupled Electron Transfer in Organic Synthesis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 2017 - 2291

Опубликована: Ноя. 23, 2021

We present here a review of the photochemical and electrochemical applications multi-site proton-coupled electron transfer (MS-PCET) in organic synthesis. MS-PCETs are redox mechanisms which both an proton exchanged together, often concerted elementary step. As such, MS-PCET can function as non-classical mechanism for homolytic bond activation, providing opportunities to generate synthetically useful free radical intermediates directly from wide variety common functional groups. introduction practitioner’s guide reaction design, with emphasis on unique energetic selectivity features that characteristic this class. then chapters oxidative N–H, O–H, S–H, C–H homolysis methods, generation corresponding neutral species. Then, reductive PCET activations involving carbonyl, imine, other X═Y π-systems, heteroarenes, where ketyl, α-amino, heteroarene-derived radicals be generated. Finally, we asymmetric catalysis materials device applications. Within each chapter, subdivide by group undergoing homolysis, thereafter type transformation being promoted. Methods published prior end December 2020 presented.

Язык: Английский

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DMSO as a C₁ Source for [2 + 2 + 1] Pyrazole Ring Construction via Metal-Free Annulation with Enaminones and Hydrazines

Organic Letters, Год журнала: 2021, Номер 24(1), С. 228 - 233

Опубликована: Дек. 15, 2021

A cascade reaction between enaminones, hydrazines, and dimethyl sulfoxide (DMSO) for the synthesis of 1,4-disubstituted pyrazoles catalyzed by molecular iodine in presence Selectfluor has been realized. DMSO plays a dual role as C1 source medium. In addition, 1,3,4-trisubstituted using aldehydes alternative building blocks also achieved.

Язык: Английский

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A visible-light-promoted metal-free approach for N–H insertions by using donor/donor diazo precursors

Green Chemistry, Год журнала: 2024, Номер 26(8), С. 4600 - 4608

Опубликована: Янв. 1, 2024

A metal-free and catalyst-free strategy is reported to achieve N–H insertions by coupling N -tosylhydrazones with diverse amines including aminopyridines, anilines, aliphatic amines, other nucleophiles such as imidazoles indoles.

Язык: Английский

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Photoinduced Rapid Multicomponent Cascade Reaction of Aryldiazonium Salts with Unactivated Alkenes and TMSN₃

Organic Letters, Год журнала: 2021, Номер 23(4), С. 1204 - 1208

Опубликована: Фев. 4, 2021

The first example of a photoinduced rapid multicomponent cascade reaction aryldiazonium salts with unactivated alkenes and trimethylsilyl azide (TMSN3) under oxidant-free conditions is described. This approach provides the synthetic route for wide range unsymmetric azo compounds. compounds are obtained in good to excellent yields mild conditions. transformation applicable various alkenes, providing an alternative synthesis control experiment demonstrates that mechanism follows radical pathway.

Язык: Английский

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Formal [4+1] Annulation of Azoalkenes with CF₃-Imidoyl Sulfoxonium Ylides and Dual Double Bond Isomerization Cascade: Synthesis of Trifluoromethyl-Containing Pyrazole Derivatives

Organic Letters, Год журнала: 2022, Номер 24(37), С. 6822 - 6827

Опубликована: Сен. 9, 2022

A straightforward strategy for the metal-free construction of trifluoromethyl-containing pyrazole derivatives has been achieved from readily available α-halo hydrazones and CF3-imidoyl sulfoxonium ylides. The cascade transformation proceeds through formal [4+1] cycloaddition followed by an unexpected dual double bond isomerization. protocol features mild conditions, easy operation, excellent substrate compatibility, good regioselectivity. synthetic utility is demonstrated scale-up reaction further elaboration obtained products.

Язык: Английский

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Electrochemical Synthesis of β-Functionalized Ketones via Ring-Opening of Cycloalkanols

Organic Letters, Год журнала: 2022, Номер 24(24), С. 4421 - 4426

Опубликована: Июнь 10, 2022

The electrochemical deconstructive functionalization of cycloalkanols with nucleophiles has been studied, which allows to occur exclusively at the β-position ketones. substrate scope includes a wide range as well diverse N, O, C, and P-centered nucleophiles, providing ready access β-functionalized ketones products. Mechanistic studies support generation α,β-unsaturated key intermediates followed by Michael addition nucleophiles.

Язык: Английский

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Photocatalytic C−C Cleavage of Methylenecyclobutanes for γ,δ‐Unsaturated Aldehydes by Strain Release

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(22)

Опубликована: Март 6, 2023

Radical additions onto olefins have surfaced as an increasingly powerful strategy for the synthesis of difunctionalized scaffolds. However, despite major advances, known approaches continue to be largely limited two manifolds, namely 1,2-difunctionalization alkenes and remote difunctionalization via hydrogen atom transfer (HAT). Herein, we describe a mechanistically distinct approach by photoinduced carbon-carbon (C-C) activation/ring-opening access γ,δ-unsaturated aldehydes from methylenecyclobutanols sulfonyl chlorides strain release. Remarkably, motif on products was easily removed another photocatalytic process, which enabled concise assembly natural product alatanone A. The synthetic utility our reflected versatile functional group tolerance, ample substrate scope, scalability. photocatalysis represents conceptually alternative existing 1,4-diversifications, with double bond remaining in thus obtained products.

Язык: Английский

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Green Synthesis of Aromatic Nitrogen-Containing Heterocycles by Catalytic and Non-Traditional Activation Methods

Molecules, Год журнала: 2023, Номер 28(10), С. 4153 - 4153

Опубликована: Май 17, 2023

Recent advances in the environmentally benign synthesis of aromatic N-heterocycles are reviewed, focusing primarily on application catalytic methods and non-traditional activation. This account features two main parts: preparation single ring N-heterocycles, their condensed analogs. Both groups include compounds with one, more N-atoms. Due to large number protocols, this focuses providing representative examples feature available methods.

Язык: Английский

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Visible‐Light‐Induced C4‐Selective Functionalization of Pyridinium Salts with Cyclopropanols

Angewandte Chemie International Edition, Год журнала: 2021, Номер 61(1)

Опубликована: Ноя. 4, 2021

Abstract The site‐selective C−H functionalization of heteroarenes is considerable importance for streamlining the rapid modification bioactive molecules. Herein, we report a general strategy visible‐light‐induced β‐carbonyl alkylation at C4 position pyridines with high site selectivity using various cyclopropanols and N‐amidopyridinium salts. In this process, hydrogen‐atom transfer between generated sulfonamidyl radicals O−H bonds generates radicals, providing efficient access to synthetically valuable β‐pyridylated (aryl)ketones, aldehydes, esters broad functional‐group tolerance. addition, mild method serves as an effective tool late‐stage complex medicinally relevant

Язык: Английский

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Copper-Promoted Aerobic Oxidative [3+2] Cycloaddition Reactions of N,N-Disubstituted Hydrazines with Alkynoates: Access to Substituted Pyrazoles

The Journal of Organic Chemistry, Год журнала: 2023, Номер 88(4), С. 2190 - 2206

Опубликована: Фев. 1, 2023

A copper-promoted aerobic oxidative [3+2] cycloaddition reaction for the synthesis of various substituted pyrazoles from N,N-disubstituted hydrazines with alkynoates in presence bases is developed. This work involves a direct C(sp3)-H functionalization and formation new C-C/C-N bonds. In this strategy, inexpensive easily available Cu2O serves as promoter air acts green oxidant. The exhibits advantages high atom step economy, regioselectivity, easy operation.

Язык: Английский

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