Nickel and Palladium Catalysis: Stronger Demand than Ever

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(2), P. 1180 - 1200

Published: Jan. 5, 2022

Key similarities and differences of Pd Ni in catalytic systems are discussed. Overall, catalyze a vast number similar C–C C–heteroatom bond-forming reactions. However, the smaller atomic radius lower electronegativity Ni, as well more negative redox potentials low-valent species, often provide higher reactivity oxidative addition or insertion reactions persistence alkyl-Ni intermediates against β-hydrogen elimination, thus enabling activation reluctant electrophiles, including alkyl electrophiles. Another key point relates to stability open-shell electronic configurations Ni(I) Ni(III) compared with Pd(I) Pd(III). Nickel very involve interconvertible Ni(n+) active species variable oxidation states (Ni(0), Ni(I), Ni(II), Ni(III)). In contrast, involving Pd(III) still relatively less developed may require facilitation by special ligands merging photo- electrocatalysis. high Pd(n+) ensure their facile reduction Pd(0) under assistance numerous reagents solvents, providing concentrations molecular Pd1(0) complexes that can reversibly aggregate into Pdn clusters nanoparticles form cocktail Pdn(0) various nuclearities (i.e., values "n"). Ni(0) strong reductants; they sensitive deactivation air other oxidizers and, consequence, operate at catalyst loadings than palladium same The ease robustness versatility for catalysis, whereas variety enables diverse uncommon reactivity, albeit requiring efforts stabilization nickel systems. As discussion, we note easily "cocktail particles" different but (Pd1, Pdn, NPs), behave species" is stable nuclearities. Undoubtedly, there stronger demand ever not only develop improved efficient catalysts also understand mechanisms

Language: Английский

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Recent Advances in the Functionalization of Terminal and Internal Alkynes

Asian Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 11(5)

Published: March 9, 2022

Abstract Alkynes are one of the most fundamental and diverse functional groups utilized in organic synthesis. Over past few years, development efficient synthetic methodologies for functionalization alkynes has been an active area research. A plethora alkyne reactions have reported literature to construct functionalized alkene scaffolds, which important building blocks many natural products, pharmaceuticals, key intermediates various transformations. In this review, we describe recent advances with emphasis on substrate scope, limitations, regioselectivity control applications these reactions. This review covers from 2016 2021.

Language: Английский

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Rh-Catalyzed [4 + 2] Annulation with a Removable Monodentate Structure toward Iminopyranes and Pyranones by C–H Annulation

Organic Letters, Journal Year: 2022, Volume and Issue: 24(16), P. 3003 - 3008

Published: April 20, 2022

The Rh-catalyzed reactions of N-pyridinyl enaminones with internal alkynes leading to the synthesis iminopyranes via a key C–H bond activation and subsequent tautomeric O–H cleavage are reported. Moreover, pyridine ring in amino group acts as an auxiliary monodentate site for this annulation can be easily removed by simple hydrolysis afford pyranones.

Language: Английский

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Synthesis of Fluorinated Compounds by Nickel-Catalyzed Defluorinative Cross-Coupling Reactions

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(18), P. 12238 - 12268

Published: Sept. 1, 2023

Organofluorine compounds have attracted extensive attention in various industrial fields due to their unique chemical and physical properties. Despite increasing demand a wide range of scientific fields, the synthesis organofluorine still faces several problems, such as difficulties handling fluorinating reagents control chemoselectivity. Compared with formation C–F bonds, activation functionalization carbon–fluorine bonds is very important but challenging topic synthetic chemistry. Due properties nickel, Ni-catalyzed defluorinative cross-couplings been greatly developed past few decades powerful strategies for construction fluorinated organic compounds. This Review summarizes advances cross-coupling aryl fluorides, gem-difluorovinyl trifluoromethyl

Language: Английский

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The Directing Group: A Tool for Efficient and Selective C–F Bond Activation

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(21), P. 12915 - 12930

Published: Oct. 8, 2021

C–F bond activation is currently considered to be "a hot topic" in many different but interconnected fields of research, due its inherent inertness and unique properties. While considerable progress has been made this particular field activating strong bonds, such as the bond, continues a challenge. Because polyfluorinated compounds are commercially available, functionalization bonds extensively studied for preparing partially fluorinated compounds, some which biologically active used functionalized materials. However, chemo- regioselective methods still required prepare useful compounds. In addition, new strategy less reactive monofluorinated remains need. Directed strategies have C–H chemistry achieve high efficiency well regioselectivity. On other hand, directed that applicable various unreactive C–O, C–N, C–F, others needed, compared with activation. Review, we focus on inert bonds.

Language: Английский

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Recent Advances in Transition‐metal‐catalyzed C−C Bond Formation via C(sp²)−F Bond Cleavage

The Chemical Record, Journal Year: 2021, Volume and Issue: 21(12), P. 3394 - 3410

Published: April 14, 2021

Abstract The activation of a carbon‐fluorine bond is one the most challenging topics in modern synthetic organic chemistry due to their low reactivity compared other carbon‐halogen bonds. In this review, we present recent developments since 2015 on cross‐coupling reactions that form C−C bonds via cleavage C( sp 2 )−F Not only conventional bonds, but also decarbonylative or carbonyl‐retentive C(acyl)−F will be introduced. This paper mainly describes new protocols for formation )−C( 3 ), and ) transition‐metal‐catalyzed

Language: Английский

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Nickel-Catalyzed Cross-Electrophile Coupling between C(sp²)–F and C(sp²)–Cl Bonds by the Reaction of ortho-Fluoro-Aromatic Amides with Aryl Chlorides

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(8), P. 4644 - 4649

Published: April 2, 2021

Ni-catalyzed cross-electrophile coupling between C(sp2)–F bonds in ortho-fluoro-substituted aromatic amides and C(sp2)–Cl aryl chlorides the presence of Zn as a reductant LiOtBu base, LiCl ZnCl2 additives is reported. The reaction displayed excellent functional group tolerance broad substrate scope. was also applicable to C(sp2)–O an tosylate triflate derivative.

Language: Английский

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Hydroxyl-Directed Rh(III)-Catalyzed C–H Functionalization: Access to Benzo[de]chromenes

Organic Letters, Journal Year: 2023, Volume and Issue: 25(10), P. 1622 - 1627

Published: March 3, 2023

A cascade oxidative annulation reaction of heterocyclic ketene aminals (HKAs) with internal alkynes catalyzed by [Cp*RhCl2]2 and oxidized Cu(OAc)2·H2O was developed to efficiently synthesize highly functionalized benzo[de]chromene derivatives in good excellent yields. The proceeded the sequential cleavage C(sp2)-H/O-H C(sp2)-H/C(sp2)-H bonds. These multicomponent reactions were regioselective. In addition, all products exhibited intense fluorescence emission solid state, they demonstrated concentration-dependent quenching presence Fe3+, indicating that these compounds could be used recognition Fe3+.

Language: Английский

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Nickel-Catalyzed Functionalization Reactions Involving C–H Bond Activation via an Amidate-Promoted Strategy and Its Extension to the Activation of C–F, C–O, C–S, and C–CN Bonds

Accounts of Chemical Research, Journal Year: 2023, Volume and Issue: 56(21), P. 3053 - 3064

Published: Oct. 11, 2023

ConspectusThe development of functionalization reactions involving the activation C-H bonds has evolved extensively due to atom and step economy associated with such reactions. Among these reactions, chelation assistance been shown provide a powerful solution serious issues reactivity regioselectivity faced in bonds. The vast majority reported thus far involved use precious metals. Kleiman Dubeck cyclonickelation azobenzene NiCp2 which an azo group directs Ni center activate ortho bond close proximity. Although this stoichiometric reaction was discovered earlier than that for other transition-metal complexes, its as catalytic delayed. No general systems were available Ni-catalyzed long time. This Account details our group's Ni(0)- Ni(II)-catalyzed chelation-assisted It also highlights how new strategy can be extended unreactive bonds.In early 2010s, we found Ni(0)-catalyzed aromatic amides contain 2-pyridinylmethylamine moiety directing alkynes results C-H/N-H oxidative annulation give isoquinolinones. In addition, combination Ni(II) catalyst 8-aminoquinoline superior developing wide variety various electrophiles. proposed include formation unstable Ni(IV) and/or Ni(III) species; generation high-valence species rare at time, but since then, many papers dealing DFT organometallic studies have appeared literature attempts understand mechanism. Based on in-depth considerations mechanism respect why N,N-bidentate is required, realized N-Ni by addition N-H Ni(0) or ligand exchange between key step. We concluded precoordination N(sp2) positions proximity permits bond. working hypothesis, carried out using KOtBu base do not specific desired isoquinolinone, amidate anion acts actual group. Remarkably, applicable C-F, C-O, C-S, C-CN.

Language: Английский

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Nickel-catalyzed reductive cross-coupling of polyfluoroarenes with alkyl electrophiles by site-selective C–F bond activation

Chinese Chemical Letters, Journal Year: 2022, Volume and Issue: 33(9), P. 4287 - 4292

Published: Feb. 3, 2022

Language: Английский

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