Synthesis, Characterization, and Catalytic Activity of Ni(0) (DQ)dtbbpy, an Air-Stable, Bifunctional Red-Light-Sensitive Precatalyst

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 5, 2025

Despite a well-established and growing body of work on nickel(0) precatalysts, the potential complexes as bifunctional precatalysts remains underexplored. In this study, we synthesized, characterized, evaluated catalytic activity (Ni(0)(DQ)dtbbpy), bifunctional, red-light-sensitive, air-stable complex. Owing to its unique photophysical properties, it effectively catalyzed etherification amination aryl bromides under 620–630 nm light irradiation, functioning both photocatalyst an active metal catalyst. Mechanistic studies density functional theory (DFT) calculations further confirmed exceptional absorption properties Ni(0)(DQ)dtbbpy in red-light region, well electron transfer process triggered by irradiation.

Language: Английский

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Ni(^4-tBustb)₃: A Robust 16-Electron Ni(0) Olefin Complex for Catalysis

Organometallics, Journal Year: 2020, Volume and Issue: 39(18), P. 3295 - 3300

Published: Sept. 10, 2020

Sixteen-electron Ni(0) complexes bearing trans-stilbene derivative ligands have been shown to display a high degree of stability toward oxidation in the solid state. A structural analysis unique family tris stilbene revealed remarkable effect steric hindrance substituents at para position unit temperature, oxidation, and degradation solution. From these analyses, Ni(4-tBustb)3 arose as long-term air-, bench-. temperature-stable complex. Importantly, presents faster kinetic profiles broader scope source, thus outperforming previously described Ni(4-CF3stb)3 variety relevant Ni-catalyzed transformations.

Language: Английский

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Ligand‐Controlled Regiodivergence in Nickel‐Catalyzed Hydroarylation and Hydroalkenylation of Alkenyl Carboxylic Acids**

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(51), P. 23306 - 23312

Published: Sept. 8, 2020

Abstract A nickel‐catalyzed regiodivergent hydroarylation and hydroalkenylation of unactivated alkenyl carboxylic acids is reported, whereby the ligand environment around metal center dictates regiochemical outcome. Markovnikov hydrofunctionalization products are obtained under mild ligand‐free conditions, with up to 99 % yield >20:1 selectivity. Alternatively, anti‐Markovnikov can be accessed a novel 4,4‐disubstituted Pyrox in excellent Both electronic steric effects on contribute high Mechanistic studies suggest change turnover‐limiting selectivity‐determining step induced by optimal ligand. DFT calculations reveal that pathway, repulsion between alkyl group minimized (by virtue it being 1° versus 2°) rate‐ regioselectivity‐determining transmetalation transition state.

Language: Английский

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Nickel-Catalyzed Reductive Cross-Coupling of Heteroaryl Chlorides and Aryl Chlorides

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(20), P. 12785 - 12793

Published: Oct. 6, 2021

We report a nickel-catalyzed cross-electrophile coupling reaction of aryl chlorides and heteroaryl enabled by synergistic combination consisting halide effects the addition magnesium salt. The relies on electronic difference between aromatic heteroaromatic partners to afford cross-coupled biaryl products using single catalyst. A variety heterocycles were amenable reaction, as well wide range chlorides, with electron-deficient performing best in reaction. Preliminary mechanistic evidence demonstrates MgCl2 is essential accelerating reduction Ni(II), that small quantities iodide lead improved yields.

Language: Английский

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Electrophilic Sulfur Reagent Design Enables Directed syn-Carbosulfenylation of Unactivated Alkenes

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(16), P. 7189 - 7197

Published: April 18, 2022

A multi-component approach to structurally complex organosulfur products is described via the nickel-catalyzed 1,2-carbosulfenylation of unactivated alkenes with organoboron nucleophiles and tailored electrophiles. The key development this transformation identification a modular N-alkyl-N-(arylsulfenyl)arenesulfonamide family sulfur Tuning electronic steric properties leaving group in these reagents controls pathway selectivity, favoring three-component coupling suppressing side reactions, as examined computational studies. unique syn-stereoselectivity differs from traditional electrophilic sulfenyl transfer processes involving thiiranium ion intermediate arises directed arylnickel(I) migratory insertion mechanism, elucidated through reaction kinetics control experiments. Reactivity regioselectivity are facilitated by collection monodentate, weakly coordinating native directing groups, including sulfonamides, alcohols, amines, amides, azaheterocycles.

Language: Английский

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Structurally Diverse Bench‐Stable Nickel(0) Pre‐Catalysts: A Practical Toolkit for In Situ Ligation Protocols**

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 62(9)

Published: Dec. 16, 2022

A flurry of recent research has centered on harnessing the power nickel catalysis in organic synthesis. These efforts have been bolstered by contemporaneous development well-defined (pre)catalysts with diverse structure and reactivity. In this report, we present ten different bench-stable, 18-electron, formally zero-valent nickel-olefin complexes that are competent pre-catalysts various reactions. Our investigation includes preparations novel, bench-stable Ni(COD)(L) (COD=1,5-cyclooctadiene), which L=quinone, cyclopentadienone, thiophene-S-oxide, fulvene. Characterization NMR, IR, single-crystal X-ray diffraction, cyclic voltammetry, thermogravimetric analysis, natural bond orbital analysis sheds light structure, bonding, properties these complexes. Applications an assortment nickel-catalyzed reactions underscore complementary nature within toolkit.

Language: Английский

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Benchtop Nickel Catalysis Invigorated by Electron-Deficient Diene Ligands

Accounts of Chemical Research, Journal Year: 2024, Volume and Issue: 57(3), P. 312 - 326

Published: Jan. 18, 2024

ConspectusDue to the rarity of precious metals like palladium, nickel catalysis is becoming an increasingly important player in organic synthesis, especially for formation bonds with sp3-hybridized carbon centers. Traditionally, catalytic processes involving active Ni(0) species have relied on Ni(COD)2 or situ reduction Ni(II) salts. However, air- and temperature-sensitive material that requires use inert-atmosphere glovebox, protocols salts using metallic organometallic reductants add additional complications reaction development.This Account chronicles development air-stable precursors as replacements reduction. Based Schrauzer's seminal discovery Ni(COD)(DQ) zerovalent organonickel complex, our research laboratories at Scripps Research Bristol Myers Squibb developed a class precatalysts based Ni(COD)(EDD) (EDD = electron-deficient diene) framework, relying steric electronic properties supporting diene render metal center stable air, moisture, even silica gel but reactive ligand substitution redox changes.The complexes can be accessed through exchange Ni(COD)2, Ni(acac)2 DIBAL-H, electrochemically via cathodic followed by addition EDD one pot. As toolkit, demonstrate reactivity equivalent enhanced compared catalyzing C–C C–N cross-couplings, Miyaura borylations, C–H activations, other transformations. Since initial report Ni(COD)(DQ), its C(sp2)–CN activation, metallophotoredox, electric field-induced cross-coupling also been demonstrated.By incorporating precatalyst toolkit into campaigns, able perform C(sp3)–S(alkyl) couplings metallonitrenoid carboamination, both which represent challenging transformations were inaccessible traditional phosphine, nitrogen, olefin ligands. Computational experimental studies how quinone ligands are hemilabile, adopting η1(O)-bound geometries relieve strain stabilize transition states intermediates; redox-active, transiently oxidize center; electron-withdrawing -donating, depending oxidation state coordination geometry. These show enable key steps beyond imparting air-stability.Since documenting activity many observed unique this precatalyst. was found offer superior cross coupling form N,N-diaryl sulfonamides preparation biaryls from aryl halides benzene Ni-mediated, base-assisted homolytic aromatic substitution.

Language: Английский

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Synthesis of Carbocyclic Compounds via a Nickel-Catalyzed Carboiodination Reaction

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(2), P. 925 - 931

Published: Jan. 5, 2021

A scalable nickel-catalyzed carboiodination reaction generating 6-membered carbocycles is reported. NiI2 and P(OEt)3, as the ligand reducing agent, provided decorated iodo-tetrahydronaphthalenes in up to 94% yield. The impact of varying electronic steric parameters on are reported a non-linear Hammett plot was obtained, supporting change rate-determining step from oxidative addition reductive elimination. Experimental DFT studies suggest that malonate group may stabilize nickel oxidative-addition complex. variety heteroatom-containing nucleophiles medicinally relevant heterocycles were easily incorporated into products via simple SN2 chemistry.

Language: Английский

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Direct Synthesis of Ketones from Methyl Esters by Nickel‐Catalyzed Suzuki–Miyaura Coupling

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(24), P. 13476 - 13483

Published: April 1, 2021

Abstract The direct conversion of alkyl esters to ketones has been hindered by the sluggish reactivity starting materials and susceptibility product towards subsequent nucleophilic attack. We have now achieved a cross‐coupling approach this transformation using nickel, bulky N‐heterocyclic carbene ligand, organoboron coupling partners. 65 bearing diverse functional groups heterocyclic scaffolds synthesized with method. Catalyst‐controlled chemoselectivity is observed for C(acyl)−O bond activation multi‐functional substrates other bonds prone cleavage Ni, including aryl ether, fluoride, N‐Ph amide groups. Density theory calculations provide mechanistic support Ni 0 /Ni II catalytic cycle demonstrate how stabilizing non‐covalent interactions between catalyst substrate are critical reaction's success.

Language: Английский

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Nickel-catalysed diversification of phosphine ligands by formal substitution at phosphorus

Chemical Science, Journal Year: 2022, Volume and Issue: 13(26), P. 7914 - 7919

Published: Jan. 1, 2022

We report a diversification strategy that enables the direct substituent exchange of tertiary phosphines. Alkylated phosphonium salts, prepared by standard alkylation phosphines, are selectively dearylated in nickel-catalysed process to access alkylphosphine products via formal substitution at phosphorus center. The reaction can be used introduce wide range alkyl substituents into both mono- and bisphosphines. also show dearylation steps conducted one-pot sequence, enabling accelerated derivatives parent ligand. phosphine converted situ air-stable borane adducts for isolation, versatile derivatisation reactions these demonstrated.

Language: Английский

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