Enhanced Reactivity of Acridinium Perchlorate: Harnessing Redox Mediators for Trace Chloride Activation in Hydrogen Atom Transfer Photocatalysis

ACS Catalysis, Год журнала: 2024, Номер 14(12), С. 9364 - 9373

Опубликована: Июнь 5, 2024

Acridinium perchlorates and tetrafluoroborates are commonly employed photocatalysts with similar photophysical characteristics. Nevertheless, perchlorate salts consistently exhibit superior catalytic performance relative to their tetrafluoroborate counterparts. In a serendipitous discovery, we unveiled the latent potential of trace chloride anions originating from acridinium salts. When coupled redox mediators like diphenyl ether or biphenyl, displayed remarkable hydrogen atom transfer (HAT) catalysis capabilities. This innovative approach enabled efficient activation diverse range unactivated C–H bonds, especially primary C(sp3)–H via Giese additions Minisci-type cross-dehydrogenative coupling reactions. Our system stands as one most HAT systems for bond activation, showcasing substrate diversity. Additionally, use stop-flow microtubing (SFMT) reactor enhanced reaction efficiency, enabling gram-scale synthesis seamless transition continuous flow processes practical-scale production.

Язык: Английский

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Hydrogen-Evolution Allylic C(sp³)–H Alkylation with Protic C(sp³)–H Bonds via Triplet Synergistic Brønsted Base/Cobalt/Photoredox Catalysis

ACS Catalysis, Год журнала: 2022, Номер 12(15), С. 9533 - 9539

Опубликована: Июль 21, 2022

Transition-metal-catalyzed allylic C(sp3)–H alkylation with carbon-center nucleophiles is a straightforward approach to C(sp3)–C(sp3) bond formation, which has found widespread application in organic synthesis. However, stoichiometric oxidants are typically required realize the transformation. Herein, by triplet synergistic merger of Brønsted base/cobalt/photoredox catalysis, mild protocol for hydrogen-evolution protic feedstocks was developed an oxidant-free manner. This operationally simple method enables direct wide range branched α-olefins diverse feedstocks. The synthetic robustness this strategy further demonstrated late-stage functionalization complex molecules and synthesis natural product dihydropallescensin D.

Язык: Английский

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Photoexcited Direct Amination/Amidation of Inert Csp³–H Bonds via Tungsten–Nickel Catalytic Relay

ACS Catalysis, Год журнала: 2022, Номер 12(18), С. 11071 - 11077

Опубликована: Авг. 26, 2022

Light alkanes are the most abundant resources in nature. It is of great significance to develop convenient methods realize conversion high value-added products. However, examples aliphatic amines derived from unactivated remain rare. This work describes a rapid construction C(sp3)–N bonds light with amine/amide electrophile reagents via high-valent tungsten and nickel catalysis efficiency. The photoexcited metal relay provides powerful tool for activation inert sp3-hybridized C–H stabilization C–Ni(III)–N intermediates.

Язык: Английский

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Organophotoredox-Catalyzed Oxidative C(sp2)–H Alkylation of N-Heteroarenes with Dihydroquinazolinones by C–C Cleavage

Synlett, Год журнала: 2023, Номер 34(11), С. 1241 - 1246

Опубликована: Фев. 8, 2023

Abstract We report a visible-light-mediated, organophotoredox-catalyzed, C(sp2)–H alkylation of N-heteroarenes with dihydroquinazolines, prepared from aliphatic ketones, under oxidative conditions. This protocol represents metal-free approach to the effective construction C–C bonds through Minisci-type reaction, formally activating native C–H bond N-heteroarene and an α-C–C readily available ketone. The mild nature this method accommodates wide variety tolerating range functional groups.

Язык: Английский

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Photocatalytic Aerobic Coupling of Azaarenes and Alkanes via Nontraditional Cl^•Generation

Organic Letters, Год журнала: 2022, Номер 24(29), С. 5276 - 5280

Опубликована: Июль 15, 2022

Herein, we demonstrate a nonconventional photocatalytic generation of Cl• from common chlorinated solvent, dichloroethane, under aerobic conditions and its successful utilization toward the cross-dehydrogenative coupling alkanes azaarenes via hydrogen atom transfer with Cl•. The process is free chloride salt, toxic oxidant, UV light. It applicable to broad spectrum substrates. proposed mechanism involving supported by series mechanistic investigations.

Язык: Английский

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An update on late-stage functionalization in today’s drug discovery

Expert Opinion on Drug Discovery, Год журнала: 2023, Номер 18(6), С. 597 - 613

Опубликована: Апрель 28, 2023

Introduction Late-stage functionalization (LSF) allows for the introduction of new chemical groups toward end a synthetic sequence, which means molecules can be rapidly accessed without laborious de novo synthesis. Over last decade, medicinal chemists have begun to implement LSF strategies into their drug discovery programs, affording benefits such as efficient access diverse libraries explore structure–activity relationships and improvement physicochemical pharmacokinetic properties.

Язык: Английский

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Iron-Catalyzed Photoredox Intermolecular Dearomatization of Benzothiazoles with Alkanes

ACS Sustainable Chemistry & Engineering, Год журнала: 2023, Номер 11(35), С. 13142 - 13148

Опубликована: Авг. 24, 2023

Benzothiazolines, with their versatile nature, serve as fundamental building blocks for the synthesis of significant biological compounds. However, methods preparation benzothiazolines from readily available starting materials are limited. An efficient benzothiazoline via photoredox-catalyzed dearomatization benzothiazole derivatives has been achieved at room temperature. This catalysis proceeds a ligand to metal charge transfer process, and FeCl3 plays dual role an indirect HAT reagent reducing agent. methodology can be conveniently scaled up, most alkylated products purified without chromatography. In addition, this process exhibited advantages low cost, high reaction efficiency, mild conditions.

Язык: Английский

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Metal- and photosensitizer-free cross-dehydrogenative coupling through photoinduced energy transfer

Green Chemistry, Год журнала: 2024, Номер 26(8), С. 4742 - 4748

Опубликована: Янв. 1, 2024

This study introduces a novel, eco-friendly method for Minisci alkylation without harmful catalysts, advancing sustainable pharmaceutical synthesis through energy transfer from heteroarenes to peroxide, offering significant environmental benefits.

Язык: Английский

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Demystifying the recent photochemical and electrochemical tricks on installing the magic methyl group: A comprehensive overview

Green Chemistry, Год журнала: 2024, Номер 26(14), С. 8161 - 8203

Опубликована: Янв. 1, 2024

The strategic installation of the “magic methyl” group has become highly desirable for drug discovery. This review summarized recent photochemical and electrochemical strategies in installing methyl group.

Язык: Английский

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Recent advances in photoredox catalytic transformations by using continuous-flow technology

CHINESE JOURNAL OF CATALYSIS (CHINESE VERSION), Год журнала: 2023, Номер 50, С. 175 - 194

Опубликована: Июль 1, 2023

Язык: Английский

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