Metallaphotoredox: The Merger of Photoredox and Transition Metal Catalysis

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(2), P. 1485 - 1542

Published: Nov. 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.

Language: Английский

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Triplet Energy Transfer Photocatalysis: Unlocking the Next Level

Chem, Journal Year: 2020, Volume and Issue: 6(8), P. 1888 - 1903

Published: Aug. 1, 2020

Language: Английский

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

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(2), P. 2487 - 2649

Published: Nov. 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.

Language: Английский

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Mechanistic Analysis of Metallaphotoredox C–N Coupling: Photocatalysis Initiates and Perpetuates Ni(I)/Ni(III) Coupling Activity

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(37), P. 15830 - 15841

Published: Aug. 4, 2020

The combined use of reaction kinetic analysis, ultrafast spectroscopy, and stoichiometric organometallic studies has enabled the elucidation mechanistic underpinnings to a photocatalytic C-N cross-coupling reaction. Steady-state spectroscopic techniques were used track excited-state evolution employed iridium photocatalyst, determine resting states both nickel catalysts, uncover photochemical mechanism for reductive activation cocatalyst. Stoichiometric along with comprehensive study reaction, including rate-driving force unveiled crucial role photocatalysis in initiating sustaining Ni(I)/Ni(III) mechanism. insights gleaned from this further discovery new photocatalyst providing >30-fold rate increase.

Language: Английский

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

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 60(33), P. 17810 - 17831

Published: Nov. 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.

Language: Английский

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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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Controlling Ni redox states by dynamic ligand exchange for electroreductive Csp3–Csp2 coupling

Science, Journal Year: 2022, Volume and Issue: 376(6591), P. 410 - 416

Published: April 21, 2022

Cross-electrophile coupling (XEC) reactions of aryl and alkyl electrophiles are appealing but limited to specific substrate classes. Here, we report electroreductive XEC previously incompatible including tertiary bromides, chlorides, aryl/vinyl triflates. Reactions rely on the merger an electrochemically active complex that selectively reacts with bromides through 1e

Language: Английский

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Catalytic synthesis of phenols with nitrous oxide

Nature, Journal Year: 2022, Volume and Issue: 604(7907), P. 677 - 683

Published: April 27, 2022

Abstract The development of catalytic chemical processes that enable the revalorization nitrous oxide (N 2 O) is an attractive strategy to alleviate environmental threat posed by its emissions 1–6 . Traditionally, N O has been considered inert molecule, intractable for organic chemists as oxidant or O-atom transfer reagent, owing harsh conditions required activation (>150 °C, 50‒200 bar) 7–11 Here we report insertion into a Ni‒C bond under mild (room temperature, 1.5–2 bar O), thus delivering valuable phenols and releasing benign This fundamentally distinct organometallic C‒O bond-forming step differs from current strategies based on reductive elimination enables alternative approach conversion aryl halides phenols. process was rendered means bipyridine-based ligands Ni centre. method robust, highly selective, able accommodate base-sensitive functionalities well permitting phenol synthesis densely functionalized halides. Although this protocol does not provide solution mitigation emissions, it represents reactivity blueprint abundant source.

Language: Английский

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Nickel Meets Aryl Thianthrenium Salts: Ni(I)-Catalyzed Halogenation of Arenes

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(18), P. 9988 - 9993

Published: May 1, 2023

Herein, a regioselective, late-stage two-step arene halogenation method is reported. We propose how unusual Ni(I)/(III) catalysis enabled by combination of aryl thianthrenium and Ni redox properties that hitherto unachieved with other (pseudo)halides. The catalyst accessed in situ from inexpensive NiCl2·6(H2O) zinc without the need supporting ligands.

Language: Английский

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General cross-coupling reactions with adaptive dynamic homogeneous catalysis

Nature, Journal Year: 2023, Volume and Issue: unknown

Published: June 14, 2023

Language: Английский

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