Electrocatalytic Access to Azetidines via Intramolecular Allylic Hydroamination: Scrutinizing Key Oxidation Steps through Electrochemical Kinetic Analysis

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(28), С. 15360 - 15369

Опубликована: Июль 10, 2023

Azetidines are prominent structural scaffolds in bioactive molecules, medicinal chemistry, and ligand design for transition metals. However, state-of-the-art methods cannot be applied to intramolecular hydroamination of allylic amine derivatives despite their underlying potential as one the most prevalent synthetic precursors azetidines. Herein, we report an electrocatalytic method sulfonamides access azetidines first time. The merger cobalt catalysis electricity enables regioselective generation key carbocationic intermediates, which could directly undergo C-N bond formation. mechanistic investigations including electrochemical kinetic analysis suggest that either catalyst regeneration by nucleophilic cyclization or second oxidation intermediate is involved rate-determining step (RDS) our protocol highlight ability electrochemistry providing ideal means mediate oxidation.

Язык: Английский

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Mechanism of Alkene Hydrofunctionalization by Oxidative Cobalt(salen) Catalyzed Hydrogen Atom Transfer

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(4), С. 2685 - 2700

Опубликована: Янв. 16, 2024

Oxidative MHAT hydrofunctionalization of alkenes provides a mild cobalt-catalyzed route to forming C–N and C–O bonds. Here, we characterize relevant salen-supported cobalt complexes their reactions with alkenes, silanes, oxidant, solvent. These stoichiometric investigations are complemented by kinetic studies the catalytic reaction catalyst speciation. We describe solution characterization an elusive cobalt(III) fluoride complex, which surprisingly is not species that reacts silane under conditions; rather, aquo complex more active. Accordingly, addition water (0.15 M) speeds reaction, show enables product formation in 2 h at −50 °C acetone. Under these conditions, resting states can be observed UV–vis spectrophotometry, including cobalt(III)-alkyl complex. It comes from transient hydride formed turnover-limiting step cycle. This readily degrades but H2; it releases H+ through bimetallic pathway explains [Co]2 dependence off-cycle reaction. In contrast, rate follows power law kobs[Co]1[silane]1. Because different [Co] degradation lower loading improves yield reducing relative unproductive silane/oxidant consumption. illuminate mechanistic details oxidative lay groundwork for understanding other mediated alkyl complexes.

Язык: Английский

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Mimicking hydrogen-atom-transfer-like reactivity in copper-catalysed olefin hydrofunctionalization

Nature Catalysis, Год журнала: 2024, Номер 7(7), С. 838 - 846

Опубликована: Июль 1, 2024

Язык: Английский

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Recent Advances in Radical Coupling Strategies Enabled by 2‐Azaallyl Anions as Super‐Electron‐Donors

Advanced Synthesis & Catalysis, Год журнала: 2024, Номер 366(7), С. 1450 - 1466

Опубликована: Фев. 14, 2024

Abstract Due to amine derivatives widely existing in numerous clinical medicines and bioactive compounds, their synthesis has received considerable attention over the past few decades. Traditional methods for of largely relied on reduction nitroarenes, amides, hydrazines, nitriles, azides. Recently, discovery 2‐azaallyl anions as super‐electron‐donors (SEDs) opened up new possibilities construction diverse carbon‐carbon carbon‐heteroatom bonds through radical coupling strategies. This breakthrough highlights potential generating radicals versatile intermediates organic synthesis. Then, hydrolysis product can easily separate corresponding derivatives. Thus, tremendous been paid C−H functionalization ketimines an alternative strategy Herein, we comprehensively summarize recent progress strategies enabled by SEDs. Their proposed mechanistic pathways, advantages, limitations are also discussed detail. 1. Introduction 2. C−C Bond Formation 2.1. Vinylation Ketimines 2.2. Arylation 2.3. Alkylation 2.3.1. Methylation 2.3.2. Other 3. C−X 3.1. C−P C−S Bonds 3.2. C−N C−O 4. Conclusions

Язык: Английский

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Catalytic hydrofunctionalizations of alkenes via hydrogen atom transfer with 3d transition metal complexes (MHAT): A pragmatic approach to recent contributions

Applied Catalysis A General, Год журнала: 2025, Номер unknown, С. 120379 - 120379

Опубликована: Май 1, 2025

Язык: Английский

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Synthesis of gem-Difluorohomoallyl Amines via a Transition-Metal-Free Defluorinative Alkylation of Benzyl Amines with Trifluoromethyl Alkenes

The Journal of Organic Chemistry, Год журнала: 2024, Номер 89(12), С. 8342 - 8356

Опубликована: Май 31, 2024

A mild and transition-metal-free defluorinative alkylation of benzyl amines with trifluoromethyl alkenes is reported. The features this protocol are easy-to-obtain starting materials, a wide range substrates, functional group tolerance as well high atom economy, thus offering strategy to access variety

Язык: Английский

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Copper-Mediated Hydrogen Atom Transfer Enabling General Catalytic Hydrofunctionalization of Olefins

Опубликована: Сен. 11, 2023

The renaissance of catalytic hydrogen atom transfer from a metal hydride (MHAT) offers advanced tools for practicing sophisticated radical chemistry on simple olefins. While 3d transition metals like cobalt, iron, and manganese have been extensively studied in MHAT, the potential copper remains unexplored. This is due to polar reactivity exhibited by classical nucleophilic Cu(I) hydrides. Here we report first examples hydrofunctionalization reactions enabled copper-mediated MHAT. Cu-MHAT process produces alkyl radicals high chemo- regioselectivity, which are subsequently captured Cu(II) species undergo coupling with an exceptionally broad scope oxygen-, nitrogen-, halogen-, carbon-based nucleophiles. distinct selectivity observed system attributed involvement Cu(II)–H species, donor that possesses substantially altered charge distribution weakened bonding contrast conventional Preliminary results suggest extension asymmetric catalysis polymerization viable. work opens up new opportunities MHAT going beyond common oxidation states.

Язык: Английский

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Visible-Light-Induced Markovnikov Hydroalkoxylation of α-Trifluoromethyl Alkenes with ortho-Diketones

The Journal of Organic Chemistry, Год журнала: 2024, Номер unknown

Опубликована: Дек. 6, 2024

We report, for the first time, a visible-light-promoted Markovnikov hydroalkoxylation of α-trifluoromethyl alkenes with 1,2-diketones. This transformation proceeded smoothly in presence tertiary amine (Et

Язык: Английский

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