Radical NHC Catalysis

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(19), P. 11984 - 11999

Published: Sept. 19, 2022

Radical/radical cross-coupling reactions represent an efficient and straightforward approach for the construction of chemical bonds accordingly have drawn increasing attention over past decades. In order to achieve synthetically useful transformations, a persistent radical should be coupled with transient in accordance effect (PRE). However, known radicals outnumber by far types free radicals, which limits widespread application PRE, until today. Thus, development between has been focus, meanwhile transition-metal catalysis successfully implemented artificially prolong lifetimes, allowing their utilization formal radical/radical cross-couplings. Complementary research field recently uncovered that organocatalytically generated NHC-derived ketyl are type catalytically radicals. NHC-catalyzed transformations aldehydes carboxylic acid derivatives enabled disclosure ever-increasing number interesting reactions, different from traditional ionic processes, offering otherwise inaccessible activation modes. These discoveries opened door NHC organocatalysis manipulation reactions. Due its obvious potential synthetic organic chemistry, it is timely provide perspective on this emerging field.

Language: Английский

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Cooperative NHC/Photoredox Catalyzed Ring‐Opening of Aryl Cyclopropanes to 1‐Aroyloxylated‐3‐Acylated Alkanes

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(48), P. 25252 - 25257

Published: Sept. 28, 2021

Cyclopropanes are an important class of building blocks in organic synthesis. Herein, a ring-opening/arylcarboxylation/acylation cascade reaction for the 1,3-difunctionalization aryl cyclopropanes enabled by cooperative NHC and organophotoredox catalysis is reported. The works on monosubstituted that contrast to heavily investigated donor-acceptor more challenging be difunctionalized. key step radical/radical cross coupling benzylic radical generated photoredox cycle with ketyl from cycle. transformation features metal-free conditions tolerates diverse range functionalities.

Language: Английский

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Single-electron carbene catalysis in redox processes

Trends in Chemistry, Journal Year: 2022, Volume and Issue: 4(4), P. 277 - 290

Published: Feb. 11, 2022

Language: Английский

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Carbene and photocatalyst-catalyzed decarboxylative radical coupling of carboxylic acids and acyl imidazoles to form ketones

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: May 23, 2022

The carbene and photocatalyst co-catalyzed radical coupling of acyl electrophile a precursor is emerging as attractive method for ketone synthesis. However, previous reports mainly limited to prefunctionalized precursors two-component coupling. Herein, an N-heterocyclic catalyzed decarboxylative carboxylic acids imidazoles disclosed, in which the are directly used precursors. could also be generated situ by reaction acid with CDI thus furnishing formally two acids. In addition, successfully extended three-component using alkene third partner via relay process. mild conditions, operational simplicity, use reacting partners make our powerful strategy construction complex ketones from readily available starting materials, late-stage modification natural products medicines.

Language: Английский

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Organic Photoredox-Catalyzed Silyl Radical Generation from Silylboronate

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(13), P. 7804 - 7810

Published: June 16, 2022

A visible-light-driven silyl radical generation method from silylboronates has been developed. The activation of with a catalytic amount mild base promoted the single-electron oxidation process to form radicals. Facile single electron transfer for borate readily occurred without hydrogen atom hydrosilane in presence various photoredox catalysts. Combining this protocol radical-mediated N-heterocyclic carbene catalysis enabled acylsilylation alkenes via relay generation. Furthermore, recent advanced methods synthesis significantly improved utility process.

Language: Английский

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NHC and visible light-mediated photoredox co-catalyzed 1,4-sulfonylacylation of 1,3-enynes for tetrasubstituted allenyl ketones

Chemical Science, Journal Year: 2022, Volume and Issue: 13(11), P. 3169 - 3175

Published: Jan. 1, 2022

The modulation of selectivity highly reactive carbon radical cross-coupling for the construction C-C bonds represents a challenging task in organic chemistry. N-Heterocyclic carbene (NHC) catalyzed transformations have opened new avenue acyl With this method, selective an with alkyl efficient was successfully realized. However, reaction radicals vinyl has been much less investigated. We herein describe NHC and visible light-mediated photoredox co-catalyzed 1,4-sulfonylacylation 1,3-enynes, providing structurally diversified valuable tetrasubstituted allenyl ketones. Mechanistic studies indicated that ketyl are formed from aroyl fluorides via oxidative quenching photocatalyst excited state, generated chemo-specific sulfonyl addition to finally, key provides

Language: Английский

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Photoinduced Acylations Via Azolium-Promoted Intermolecular Hydrogen Atom Transfer

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(3), P. 1535 - 1541

Published: Jan. 10, 2023

Photoinduced hydrogen atom transfer (HAT) has been developed as a powerful tool to generate synthetically valuable radical species. The direct photoexcitation of ketones known promote HAT or acyl radicals through Norrish-type pathways, but these modalities remain severely limited by side reactions. We report herein catalyst- and transition metal-free method for the acylation C-H bonds that leverages unique properties stable, isolable azolium Specifically, salts are shown undergo an intermolecular regioselective upon LED irradiation with range substrates bearing active followed C-C bond formation afford ketones. Experimental computational studies support facile intersystem crossing access triplet diradical species selective radical-radical cross-coupling.

Language: Английский

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Recent advances in combining photo- and N-heterocyclic carbene catalysis

Chemical Science, Journal Year: 2023, Volume and Issue: 14(46), P. 13367 - 13383

Published: Jan. 1, 2023

This review summarizes recent advances in combining photo- and N-heterocyclic carbene catalysis, as well provides an outlook on future opportunities challenges.

Language: Английский

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Radical Reactions with N-Heterocyclic Carbene (NHC)-Derived Acyl Azoliums for Access to Multifunctionalized Ketones

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(11), P. 8270 - 8293

Published: May 13, 2024

As one of the most important key intermediates, NHC-bound acylazolium-based ionic transformations have been intensively explored in past two decades. With expeditious development NHC-catalyzed radical recent years, acylazolium chemistry has reached another level, with number relevant publications increasing significantly. However, a summary focused on acylations NHC-derived acyl azoliums classified according to mechanistic difference not reported. Such detailed classification and deep analysis provide opportunities for better understanding history trend this field. In review, reactions N-heterocyclic carbene (NHC)-derived are systematically introduced. The achievements challenges within area also summarized discussed at end.

Language: Английский

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Remote site-selective arene C–H functionalization enabled by N-heterocyclic carbene organocatalysis

Nature Catalysis, Journal Year: 2024, Volume and Issue: 7(8), P. 900 - 911

Published: July 11, 2024

Language: Английский

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