Enantioselective C(sp²)–C(sp³) Bond Construction by Ni Catalysis

Accounts of Chemical Research, Год журнала: 2024, Номер 57(5), С. 751 - 762

Опубликована: Фев. 12, 2024

ConspectusAfter decades of palladium dominating the realm transition-metal-catalyzed cross-coupling, recent years have witnessed exciting advances in development new nickel-catalyzed cross-coupling reactions to form C(sp3) centers. Nickel possesses distinct properties compared with palladium, such as facile single-electron transfer electrophiles and rapid C–C reductive elimination from NiIII. These properties, among others, make nickel particularly well-suited for (RCC) which two are coupled an exogenous reductant is used turn over metal catalyst. Ni-catalyzed RCCs use readily available stable starting materials exhibit good functional group tolerance, makes them appealing applications synthesis complex molecules. Building upon foundational work by groups Kumada, Durandetti, Weix, well advancements enantioselective redox-neutral cross-couplings led Fu co-workers, we initiated a program explore feasibility developing highly RCCs. Our research has also been driven keen interest unraveling factors contributing enantioinduction electrophile activation seek avenues advancing our understanding further these reactions.In first part this Account, organize reported methods on basis identity electrophiles, including benzylic chlorides, N-hydroxyphthalimide (NHP) esters, α-chloro esters nitriles. We highlight how selection specific chiral ligands plays pivotal role achieving high cross-selectivity enantioselectivity. In addition, show that reduction can be accomplished not only heterogeneous reductants, Mn0, but soluble organic tetrakis(dimethylamino)ethylene (TDAE), electrochemically. The homogeneous TDAE, suited studying mechanism transformation. Although Account primarily focuses RCCs, using trifluoroborate (BF3K) salts radical precursors dual-Ni/photoredox systems.At end summarize relevant mechanistic studies closely related asymmetric alkenylation developed laboratory provide context between others. discuss ligand influence rates mechanisms mode generation optimize yield RCC. endeavors offer insights intricate at play goal rate improve substrate scope anticipate share guidance field.

Язык: Английский

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Mechanisms of Photoredox Catalysis Featuring Nickel–Bipyridine Complexes

ACS Catalysis, Год журнала: 2024, Номер 14(11), С. 9055 - 9076

Опубликована: Май 29, 2024

Metallaphotoredox catalysis can unlock useful pathways for transforming organic reactants into desirable products, largely due to the conversion of photon energy chemical potential drive redox and bond transformation processes. Despite importance these processes cross-coupling reactions other transformations, their mechanistic details are only superficially understood. In this review, we have provided a detailed summary various photoredox mechanisms that been proposed date Ni-bipyridine (bpy) complexes, focusing separately on photosensitized direct excitation reaction By highlighting multiple key findings, depict how mechanisms, which ultimately define substrate scope, themselves defined by ground- excited-state geometric electronic structures Ni-based intermediates. We further identify knowledge gaps motivate future studies development synergistic research approaches spanning physical, organic, inorganic chemistry communities.

Язык: Английский

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Asymmetric Cross-Coupling of Aldehydes with Diverse Carbonyl or Iminyl Compounds by Photoredox-Mediated Cobalt Catalysis

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(15), С. 10857 - 10867

Опубликована: Апрель 8, 2024

The asymmetric cross-coupling of unsaturated bonds, hampered by their comparable polarity and reactivity, as well the scarcity efficient catalytic systems capable diastereo- enantiocontrol, presents a significant hurdle in organic synthesis. In this study, we introduce highly adaptable photochemical cobalt catalysis framework that facilitates chemo- stereoselective reductive cross-couplings between common aldehydes with broad array carbonyl iminyl compounds, including N-acylhydrazones, aryl ketones, aldehydes, α-keto esters. Our methodology hinges on synergistic mechanism driven photoredox-induced single-electron reduction subsequent radical–radical coupling, all precisely guided chiral catalyst. Various optically enriched β-amino alcohols unsymmetrical 1,2-diol derivatives (80 examples) have been synthesized good yields (up to 90% yield) high stereoselectivities >20:1 dr, 99% ee). Of particular note, approach accomplishes unattainable transformations disparate partners without reliance any external photosensitizer, thereby further emphasizing its versatility cost-efficiency.

Язык: Английский

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Ni-Catalyzed Enantioselective Desymmetrization: Development of Divergent Acyl and Decarbonylative Cross-Coupling Reactions

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

Опубликована: Янв. 14, 2025

Ni-catalyzed asymmetric reductive cross-coupling reactions provide rapid and modular access to enantioenriched building blocks from simple electrophile precursors. Reductive coupling that can diverge through a common organometallic intermediate two distinct families of products are particularly versatile but underdeveloped. Here, we describe the development bis(oxazoline) ligand enables desymmetrization meso-anhydrides. When secondary benzylic electrophiles employed, doubly stereoselective acyl proceeds give ketone with catalyst control over three newly formed stereogenic centers. Alternatively, use primary alkyl halides in presence an additional halogen atom transfer results decarbonylative alkylation β-alkyl acids. Analysis reaction rates for range both catalysts substrates supports notion tuning different activation steps is required enhanced performance. These studies illustrate how design Ni-acyl either or highlight dual systems be used engage unactivated coupling.

Язык: Английский

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Enantioselective Reductive Cross-Couplings of Olefins by Merging Electrochemistry with Nickel Catalysis

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(44), С. 23910 - 23917

Опубликована: Окт. 26, 2023

The merger of electrochemistry and transition metal catalysis has emerged as a powerful tool to join two electrophiles in an enantioselective manner. However, the development electroreductive cross-couplings olefins remains challenge. Inspired by advantages synergistic use with nickel catalysis, we present here Ni-catalyzed cross-coupling acrylates aryl halides alkyl bromides, which affords chiral α-aryl carbonyls good excellent enantioselectivity. Additionally, this catalytic reaction can be applied (hetero)aryl chlorides, is difficult achieve other methods. combination cyclic voltammetry analysis electrode potential studies suggests that NiI species activates oxidative addition bromides single-electron transfer.

Язык: Английский

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Cross-Electrophile Coupling: Principles, Methods, and Applications in Synthesis

Chemical Reviews, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 26, 2024

Cross-electrophile coupling (XEC), defined by us as the cross-coupling of two different σ-electrophiles that is driven catalyst reduction, has seen rapid progression in recent years. As such, this review aims to summarize field from its beginnings up until mid-2023 and provide comprehensive coverage on synthetic methods current state mechanistic understanding. Chapters are split type bond formed, which include C(sp

Язык: Английский

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Electrocatalytic Asymmetric Nozaki–Hiyama–Kishi Decarboxylative Coupling: Scope, Applications, and Mechanism

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(7), С. 4872 - 4882

Опубликована: Фев. 7, 2024

The first general enantioselective alkyl-Nozaki-Hiyama-Kishi (NHK) coupling reactions are disclosed herein by employing a Cr-electrocatalytic decarboxylative approach. Using easily accessible aliphatic carboxylic acids (via redox-active esters) as alkyl nucleophile synthons, in combination with aldehydes and enabling additives, chiral secondary alcohols produced good yield high enantioselectivity under mild reductive electrolysis. This reaction, which cannot be mimicked using stoichiometric metal or organic reductants, tolerates broad range of functional groups is successfully applied to dramatically simplify the synthesis multiple medicinally relevant structures natural products. Mechanistic studies revealed that this asymmetric e-NHK reaction was enabled catalytic tetrakis(dimethylamino)ethylene, acts key mediator mediate electroreduction Cr

Язык: Английский

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Nickel-Catalyzed Enantioselective Reductive Arylation of Common Ketones

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(19), С. 12895 - 12900

Опубликована: Май 2, 2024

A nickel complex of chiral bisoxazolines catalyzed the stereoselective reductive arylation ketones in high enantioselectivity. range common acyclic and cyclic reacted without aid directing groups. Mechanistic studies using isolated a bis(oxazoline) (L)Ni(Ar)Br revealed that Mn reduction was not needed, while Lewis acidic titanium alkoxides were critical to ketone insertion.

Язык: Английский

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Enantiocovergent Cross-Coupling Reaction with 1,4-Dihydropyridine Derivatives via Photoinduced Nickel Catalysis

ACS Catalysis, Год журнала: 2024, Номер 14(5), С. 3278 - 3286

Опубликована: Фев. 15, 2024

Herein, we reported the enantioconvergent Csp3–Csp2 cross-coupling reaction with 1,4-dihydropyridine (DHP) derivatives via photoredox/nickel dual catalysis to access chiral products good yield and enantioselectivity. The operationally simple was carried out under mild conditions functional group tolerance. Due use of a stoichiometric equivalent aryl/alkenyl halides as coupling partners, sequential iterative synthesis could be achieved smoothly in one pot for position isomers stereoisomers. In proposed mechanism, kinetic experiments mechanistic studies indicated that radical generation, depended on excited photocatalyst DHP, rate-determining step.

Язык: Английский

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Alkyl Cyclopropyl Ketones in Catalytic Formal [3 + 2] Cycloadditions: The Role of SmI₂ Catalyst Stabilization

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(18), С. 12799 - 12807

Опубликована: Апрель 25, 2024

Alkyl cyclopropyl ketones are introduced as versatile substrates for catalytic formal [3 + 2] cycloadditions with alkenes and alkynes previously unexplored enyne partners, efficiently delivering complex, sp3-rich products. The key to effectively engaging this relatively unreactive new substrate class is the use of SmI2 a catalyst in combination substoichiometric amounts Sm0; latter likely acting prevent deactivation by returning SmIII cycle. In absence Sm0, background degradation can outrun product formation. For most recalcitrant alkyl ketones, catalysis "switched-on" using these robust conditions, otherwise unattainable products delivered. Combined experimental computational studies have been used identify probe reactivity trends among including more complex bicyclic which react quickly various partners give addition establishing burgeoning field catalysis, our study provides vital mechanistic insight robust, practical approaches nascent SmI2.

Язык: Английский

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