Metallaphotoredox: The Merger of Photoredox and Transition Metal Catalysis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 1485 - 1542

Опубликована: Ноя. 18, 2021

The merger of photoredox catalysis with transition metal catalysis, termed metallaphotoredox has become a mainstay in synthetic methodology over the past decade. Metallaphotoredox combined unparalleled capacity for bond formation broad utility photoinduced electron- and energy-transfer processes. Photocatalytic substrate activation allowed engagement simple starting materials metal-mediated bond-forming Moreover, electron or energy transfer directly key organometallic intermediates provided novel modes entirely complementary to traditional catalytic platforms. This Review details contextualizes advancements molecule construction brought forth by metallaphotocatalysis.

Язык: Английский

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Photons or Electrons? A Critical Comparison of Electrochemistry and Photoredox Catalysis for Organic Synthesis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 2487 - 2649

Опубликована: Ноя. 9, 2021

Redox processes are at the heart of synthetic methods that rely on either electrochemistry or photoredox catalysis, but how do and catalysis compare? Both approaches provide access to high energy intermediates (e.g., radicals) enable bond formations not constrained by rules ionic 2 electron (e) mechanisms. Instead, they 1e mechanisms capable bypassing electronic steric limitations protecting group requirements, thus enabling chemists disconnect molecules in new different ways. However, while providing similar intermediates, differ several physical chemistry principles. Understanding those differences can be key designing transformations forging disconnections. This review aims highlight these similarities between comparing their underlying principles describing impact electrochemical photochemical methods.

Язык: Английский

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Recent advances in visible light-activated radical coupling reactions triggered by (i) ruthenium, (ii) iridium and (iii) organic photoredox agents

Chemical Society Reviews, Год журнала: 2021, Номер 50(17), С. 9540 - 9685

Опубликована: Янв. 1, 2021

Visible light-activated reactions continue to expand and diversify. The example shown here is a Birch reduction achieved by organophotoredox reagents.

Язык: Английский

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Strategies to Generate Nitrogen-centered Radicals That May Rely on Photoredox Catalysis: Development in Reaction Methodology and Applications in Organic Synthesis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 2353 - 2428

Опубликована: Окт. 8, 2021

For more than 70 years, nitrogen-centered radicals have been recognized as potent synthetic intermediates. This review is a survey designed for use by chemists engaged in target-oriented synthesis. summarizes the recent paradigm shift access to and application of N-centered enabled visible-light photocatalysis. broadens streamlines approaches many small molecules because photocatalysis conditions are mild. Explicit attention paid innovative advances N–X bonds radical precursors, where X = Cl, N, S, O, H. clarity, key mechanistic data noted, available. Synthetic applications limitations summarized illuminate tremendous utility photocatalytically generated radicals.

Язык: Английский

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Ligand‐to‐Metal Charge Transfer (LMCT) Photochemistry at 3d‐Metal Complexes: An Emerging Tool for Sustainable Organic Synthesis

ChemCatChem, Год журнала: 2022, Номер 14(19)

Опубликована: Авг. 11, 2022

Abstract Despite the rich photochemistry of 3d‐metal complexes, utilization excited‐state reactivity these compounds in organic synthesis has been historically overlooked. The advent photoredox catalysis changed perception synthetic chemists towards photochemistry, and nowadays potential photoinduced, outer‐sphere single‐electron transfer events is widely recognized. More recently, an emerging new mode photoactivation taken spotlight, based on inner‐sphere triggered by population ligand‐to‐metal charge‐transfer (LMCT) excited states. Contrarily to photoredox, LMCT‐activation does not rely matching redox potentials, offers unique profiles particularly well suited Earth‐abundant metal complexes. Those appealing features are propelling development methods using this blueprint generate highly reactive open‐shell species under mild conditions. aim contribution provide a didactical tool for comprehension concept facilitate methodologies achieve sustainable chemical transformations.

Язык: Английский

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Nickel‐Catalyzed C‐Heteroatom Cross‐Coupling Reactions under Mild Conditions via Facilitated Reductive Elimination

Angewandte Chemie International Edition, Год журнала: 2020, Номер 60(33), С. 17810 - 17831

Опубликована: Ноя. 30, 2020

The formation of C-heteroatom bonds represents an important type bond-forming reaction in organic synthesis and often provides a fast efficient access to privileged structures found pharmaceuticals, agrochemical materials. In contrast conventional Pd- or Cu-catalyzed cross-couplings under high-temperature conditions, recent advances homo- heterogeneous Ni-catalyzed formations mild conditions are particularly attractive from the standpoint sustainability practicability. generation NiIII excited NiII intermediates facilitate reductive elimination step achieve cross-couplings. This review overview state-of-the-art approaches for bond highlights developments photoredox nickel dual catalysis involving SET energy transfer processes; photoexcited catalysis; electro graphitic carbon nitride (mpg-CN), metal frameworks (MOFs) semiconductor quantum dots (QDs); as well more zinc catalyzed reactions.

Язык: Английский

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Dual Metalation in a Two-Dimensional Covalent Organic Framework for Photocatalytic C–N Cross-Coupling Reactions

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(17), С. 7822 - 7833

Опубликована: Апрель 21, 2022

Covalent organic frameworks (COFs) are promising hosts in heterogeneous catalysis. Herein, we report a dual metalation strategy single two-dimensional-COF TpBpy for performing variety of C–N cross-coupling reactions. [Ir(ppy)2(CH3CN)2]PF6 [ppy = 2-phenylpyridine], containing two labile CH3CN groups, and NiCl2 used as iridium nickel-metal precursors, respectively, postsynthetic decoration the COF. Moving from traditional approach, focus on COF-backbone host visible-light-mediated nickel-catalyzed coupling The controlled recyclability without deactivation both catalytic centers unique with respect to previously reported strategies. We performed various photoluminescence, electrochemical, kinetic, Hammett correlation studies understand salient features catalyst reaction mechanism. Furthermore, theoretical calculations delineated feasibility electron transfer Ir center Ni inside confined pore metal anchoring within COF backbone prevented nickel-black formation. developed protocol enables selective reproducible diverse range amines (aryl, heteroaryl, alkyl), carbamides, sulfonamides electron-rich, neutral, poor (hetero) aryl iodides up 94% isolated yield. can also be gram scale. establish practical implementation this have applied synthetic late-stage diversification derivatives ibuprofen, naproxen, gemfibrozil, helional, amino acids. methodology could synthesize pharmacophore N,5-diphenyloxazol-2-amine Food Drug Administration-approved drugs, including flufenamic acid, flibanserin, tripelennamine.

Язык: Английский

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Nickel and Palladium Catalysis: Stronger Demand than Ever

ACS Catalysis, Год журнала: 2022, Номер 12(2), С. 1180 - 1200

Опубликована: Янв. 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

Язык: Английский

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Photophysical Properties and Redox Potentials of Photosensitizers for Organic Photoredox Transformations

Synlett, Год журнала: 2021, Номер 33(12), С. 1154 - 1179

Опубликована: Фев. 15, 2021

Abstract Photoredox catalysis has proven to be a powerful tool in synthetic organic chemistry. The rational design of photosensitizers with improved photocatalytic performance constitutes major advancement photoredox transformations. This review summarizes the fundamental ground-state and excited-state photophysical electrochemical attributes molecular photosensitizers, which are important determinants their reactivity.

Язык: Английский

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Oxidative Addition of Aryl Halides to a Ni(I)-Bipyridine Complex

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(12), С. 5575 - 5582

Опубликована: Март 17, 2022

The oxidative addition of aryl halides to bipyridine- or phenanthroline-ligated nickel(I) is a commonly proposed step in nickel catalysis. However, there scarcity complexes this type that both are well-defined and undergo with halides, hampering organometallic studies process. We report the synthesis Ni(I) complex, [(CO2Etbpy)NiICl]4 (1). Its solution-phase speciation characterized by significant population monomer redox equilibrium can be perturbed π-acceptors σ-donors. 1 reacts readily bromides, mechanistic consistent pathway proceeding through an initial → Ni(III) form species. Such process was demonstrated stoichiometrically for first time, affording structurally complex.

Язык: Английский

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