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

ACS Catalysis, Год журнала: 2024, Номер 14(11), С. 8270 - 8293

Опубликована: Май 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.

Язык: Английский

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Copper-Catalyzed Radical Relay 1,3-Carbocarbonylation across Two Distinct C═C Bonds

Organic Letters, Год журнала: 2024, Номер 26(15), С. 3014 - 3019

Опубликована: Март 28, 2024

The radical relay provides an effective paradigm for intermolecular assembly to achieve functionalization across remote chemical bonds. Herein, we report the first 1,3-carbocarbonylation of α-carbonyl alkyl bromides two separate C═C reaction is highly chemo- and regioselective, with C(sp3)–C(sp3) bonds one C═O bond formed in a single orchestrated operation. In addition, synthesis method under mild conditions using inexpensive copper as catalyst allows facile access structurally diverse products. plausible mechanism investigated through series control experiments, including trapping, clock critical intermediate 18O labeling experiment.

Язык: Английский

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1H-1,2,3-Triazol-5-ylidenes as Catalytic Organic Single-Electron Reductants

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(5), С. 2933 - 2938

Опубликована: Янв. 22, 2024

Most of the known single-electron reductants are either metal based reagents, used in a stoichiometric amount, or combination an organic species and photocatalyst. Here we report that 1

Язык: Английский

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Photoinduced C(sp³)−H Bicyclopentylation Enabled by an Electron Donor–Acceptor Complex‐Mediated Chemoselective Three‐Component Radical Relay

Angewandte Chemie International Edition, Год журнала: 2024, Номер unknown

Опубликована: Апрель 10, 2024

The photoredox electron donor-acceptor (EDA) complex-mediated radical coupling reaction has gained prominence in the field of organic synthesis, finding widespread application two-component reactions. However, EDA complex-promoted multi-component reactions are not well developed with only a limited number examples have been reported. Herein, we report photoinduced and highly chemoselective three-component arylalkylation [1.1.1]propellane, which allows direct functionalization C(sp

Язык: Английский

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Synthesis of γ-Oxo-phosphonates via N-Heterocyclic Carbene-Catalyzed Acylphosphorylation of Alkenes

Organic Letters, Год журнала: 2024, Номер 26(11), С. 2197 - 2201

Опубликована: Март 7, 2024

In this study, we present an N-heterocyclic carbene-catalyzed method for the radical acylphosphorylation of alkenes. Electrochemical investigations were employed to identify appropriate class oxime phosphonates capable undergoing a single-electron transfer (SET) with Breslow enolates. The resulting phosphoryl radicals effectively coupled diverse styrenes and aldehydes yield variety γ-oxo-phosphonates. Both clock experiments electrochemical studies support our reaction design, plausible mechanism organocatalytic transformation is proposed.

Язык: Английский

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NHC-Mediated Radical Acylation Catalyzed by Thiamine- and Flavin-Dependent Enzymes

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Апрель 15, 2025

Cross-coupling reactions between short-lifetime radicals are challenging in organic chemistry. Here, we report the development of an N-heterocyclic carbene (NHC)-mediated radical coupling reaction based on catalytic machinery thiamine- and flavin-dependent enzymes. Through a series enzyme screenings, found that acetolactate synthase from Thermobispora bispora (TbALS) its engineered variants exhibit promising activity toward abiotic acylation α-bromo carbonyl compounds. Notably, TbALS variant has higher for small nonaromatic substrates despite forming less stable intermediates. Furthermore, system can be applied to photocatalytic utilizing photoredox properties FAD. Nonbenzylic alkyl generated N-acyloxyphthalimides efficiently converted into corresponding dialkyl ketones under irradiation blue LED. These findings highlight utility enzymes achieving selective cross-coupling radicals.

Язык: Английский

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Photoinduced C(sp³)−H Bicyclopentylation Enabled by an Electron Donor–Acceptor Complex‐Mediated Chemoselective Three‐Component Radical Relay

Angewandte Chemie, Год журнала: 2024, Номер 136(39)

Опубликована: Апрель 10, 2024

Abstract The photoredox electron donor–acceptor (EDA) complex‐mediated radical coupling reaction has gained prominence in the field of organic synthesis, finding widespread application two‐component reactions. However, EDA complex‐promoted multi‐component reactions are not well developed with only a limited number examples have been reported. Herein, we report photoinduced and highly chemoselective three‐component arylalkylation [1.1.1]propellane, which allows direct functionalization C(sp 3 )−H bicyclo[1.1.1]pentanes (BCP)‐aryl groups under mild conditions. A variety unnatural α‐amino acids, featuring structurally diversified 1,3‐disubstituted BCP moieties, were synthesized single‐step process. Notably, leveraging high tension release unstable transient aryl undergoes rapid conversion into relatively stable tertiary alkyl radical, consequently, competing side‐reaction was entirely suppressed. strategic use this approach would be useful for design diverse It is noteworthy that late‐stage incorporation pharmacophores peptides achieved both liquid‐phase solid‐phase This advancement anticipated to significant potential future development peptide drugs.

Язык: Английский

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Silver‐Catalyzed Decarboxylative Acylfluorination of Two Alkenes with Ketonic Acids

Advanced Synthesis & Catalysis, Год журнала: 2024, Номер 366(7), С. 1643 - 1648

Опубликована: Янв. 23, 2024

Abstract An acylative fluorination of two different alkenes is developed, assisted by the interaction silver catalyst and Selectflour. Various α‐ketonic acids can be decarboxylated to form acyl radicals at 35 °C, sequentially add electron‐deficient electron‐ rich provide benzyl fluorinated compounds containing diversified functional groups.

Язык: Английский

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Stereoselective Radical Acylfluoroalkylation of Bicyclobutanes via N‐Heterocyclic Carbene Catalysis

Angewandte Chemie International Edition, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 14, 2024

Cyclobutanes are prominent structural components in natural products and drug molecules. With the advent of strain-release-driven synthesis, ring-opening reactions bicyclo[1.1.0]butanes (BCBs) provide an attractive pathway to construct these three-dimensional structures. However, stereoselective difunctionalization central C-C σ-bonds remains challenging. Reported herein is a covalent-based organocatalytic strategy that exploits radical NHC catalysis achieve diastereoselective acylfluoroalkylation BCBs under mild conditions. The Breslow enolate acts as single electron donor provides NHC-bound ketyl with appropriate steric hindrance, which effectively distinguishes between two faces transient cyclobutyl radicals. This operationally simple method tolerates various fluoroalkyl reagents common functional groups, providing straightforward access polysubstituted cyclobutanes (75 examples, up >19 : 1 d.r.). combined experimental theoretical investigations this system confirm formation NHC-derived understanding how radical-radical coupling occurs.

Язык: Английский

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Cooperative Photoredox and N-Heterocyclic Carbene Catalysis Suzuki–Miyaura-Type Reaction: Radical Coupling of Aroyl Fluorides and Alkyl Boronic Acids

Organic Letters, Год журнала: 2024, Номер 26(8), С. 1728 - 1733

Опубликована: Фев. 22, 2024

An intermolecular Suzuki–Miyaura-type reaction of benzoyl fluorides with alkyl boronic acids to synthetic ketone was revealed by cooperative N-heterocyclic carbene (NHC) and photoredox catalysis. Various boric can be converted into radicals without external oxidants or activators. Moreover, the catalytic system feasible for difunctionalization styrenes via a radical relay process. Mechanistic experiments suggested that benzoate anion intermediate might play unique role in this system.

Язык: Английский

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