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

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(12), P. 9364 - 9373

Published: June 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.

Language: 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, Journal Year: 2022, Volume and Issue: 12(15), P. 9533 - 9539

Published: July 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.

Language: Английский

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

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(18), P. 11071 - 11077

Published: Aug. 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.

Language: Английский

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

Green Chemistry, Journal Year: 2024, Volume and Issue: 26(8), P. 4742 - 4748

Published: Jan. 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.

Language: Английский

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

Organic Letters, Journal Year: 2022, Volume and Issue: 24(29), P. 5276 - 5280

Published: July 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.

Language: Английский

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

Synlett, Journal Year: 2023, Volume and Issue: 34(11), P. 1241 - 1246

Published: Feb. 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.

Language: Английский

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

Expert Opinion on Drug Discovery, Journal Year: 2023, Volume and Issue: 18(6), P. 597 - 613

Published: April 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.

Language: Английский

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Iron-Catalyzed Photoredox Intermolecular Dearomatization of Benzothiazoles with Alkanes

ACS Sustainable Chemistry & Engineering, Journal Year: 2023, Volume and Issue: 11(35), P. 13142 - 13148

Published: Aug. 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.

Language: Английский

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

Green Chemistry, Journal Year: 2024, Volume and Issue: 26(14), P. 8161 - 8203

Published: Jan. 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.

Language: Английский

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Photoinduced Cobaloxime-Catalyzed Regio- and Diastereoselective Hydrogen-Evolution C(sp³)–H Phosphorylation of Bicyclo[1.1.0]butanes

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 15, 2025

Radical-initiated functionalization of bicyclo[1.1.0]butanes (BCBs) is a straightforward approach to accessing diverse cyclobutane derivatives. However, selective C(sp3)–H at the C2 position BCBs remains scarce. Herein, mild protocol for hydrogen-evolution phosphorylation with enabled by photoinduced cobaloxime catalysis was realized in regio- and diastereoselective manner. This oxidant- additional photocatalyst-free method wide range diarylphosphine oxides. The mechanism studied via control experiments DFT calculation. Moreover, efficiency this highlighted synthesis high-value, structurally complex molecules.

Language: Английский

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