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

ChemCatChem, Journal Year: 2022, Volume and Issue: 14(19)

Published: Aug. 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.

Language: Английский

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Transition-Metal-Catalyzed C–S, C–Se, and C–Te Bond Formations via Cross-Coupling and Atom-Economic Addition Reactions. Achievements and Challenges

Chemical Reviews, Journal Year: 2022, Volume and Issue: 122(21), P. 16110 - 16293

Published: Sept. 16, 2022

In the present review, we discuss recent progress in field of C–Z bond formation reactions (Z = S, Se, Te) catalyzed by transition metals. Two complementary methodologies are considered─catalytic cross-coupling and catalytic addition reactions. The development advanced systems is aimed at improved catalyst efficiency, reduced loading, better cost environmental concerns, higher selectivity yields. important rise research efforts sustainability green chemistry areas critically assessed. paramount role mechanistic studies a new generation addressed, key achievements, problems, challenges summarized for this field.

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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Emerging concepts in photocatalytic organic synthesis

iScience, Journal Year: 2021, Volume and Issue: 24(3), P. 102209 - 102209

Published: Feb. 21, 2021

Visible light photocatalysis has become a powerful tool in organic synthesis that uses photons as traceless, sustainable reagents. Most of the activities field focus on development new reactions via common photoredox cycles, but recently number exciting concepts and strategies entered less charted territories. We survey approaches enable use longer wavelengths show wavelength intensity are import parameters tuning reactivity photocatalyst to control or change selectivity chemical reactions. In addition, we discuss recent efforts substitute strong reductants, such elemental lithium sodium, by technological advances field.

Language: Английский

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Acridine‐Functionalized Covalent Organic Frameworks (COFs) as Photocatalysts for Metallaphotocatalytic C−N Cross‐Coupling

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(21)

Published: Feb. 21, 2022

Covalent organic frameworks (COFs) are structurally tuneable, porous and crystalline polymers constructed through the covalent attachment of small building blocks as elementary units. Using myriad such blocks, a broad spectrum functionalities has been applied for COF syntheses applications, including heterogeneous catalysis. Herein, we report synthesis new family COFs using novel acridine linker benzene-1,3,5-tricarbaldehyde derivatives bearing variable number hydroxy groups. With absorption in visible light region, were photocatalysts metallaphotocatalytic C-N cross-coupling. The fully β-ketoenamine linked showed highest activity, due to increased charge separation upon irradiation. good excellent yields several aryl bromides, recyclability even catalyzed transformation presence green energy source.

Language: Английский

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Using Data Science To Guide Aryl Bromide Substrate Scope Analysis in a Ni/Photoredox-Catalyzed Cross-Coupling with Acetals as Alcohol-Derived Radical Sources

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(2), P. 1045 - 1055

Published: Jan. 5, 2022

Ni/photoredox catalysis has emerged as a powerful platform for C(sp2)–C(sp3) bond formation. While many of these methods typically employ aryl bromides the C(sp2) coupling partner, variety aliphatic radical sources have been investigated. In principle, reactions enable access to same product scaffolds, but it can be hard discern which method because nonstandardized sets are used in scope evaluation. Herein, we report Ni/photoredox-catalyzed (deutero)methylation and alkylation halides where benzaldehyde di(alkyl) acetals serve alcohol-derived sources. Reaction development, mechanistic studies, late-stage derivatization biologically relevant chloride, fenofibrate, presented. Then, describe integration data science techniques, including DFT featurization, dimensionality reduction, hierarchical clustering, delineate diverse succinct collection that is representative chemical space substrate class. By superimposing examples from published on this space, identify areas sparse coverage high versus low average yields, enabling comparisons between prior art new method. Additionally, demonstrate systematically selected quantify population-wide reactivity trends reveal possible functional group incompatibility with supervised machine learning.

Language: Английский

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Metallaphotoredox catalysis for sp³C–H functionalizations through hydrogen atom transfer (HAT)

Chemical Society Reviews, Journal Year: 2023, Volume and Issue: 52(12), P. 4099 - 4120

Published: Jan. 1, 2023

sp 3 C–H functionalizations under the combination of photocatalytic HAT and transition metal catalysis.

Language: Английский

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Modular Access to Chiral α-(Hetero)aryl Amines via Ni/Photoredox-Catalyzed Enantioselective Cross-Coupling

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(19), P. 8797 - 8806

Published: May 3, 2022

Chiral α-aryl N-heterocycles are commonly found in natural products, pharmaceutical agents, and chiral catalysts but remain challenging to access via asymmetric catalysis. Herein, we report a general modular approach for the direct enantioselective α-arylation of saturated azacycles acyclic N-alkyl benzamides nickel/photoredox dual This process exploits hydrogen atom transfer ability photoeliminated chlorine radicals convert corresponding α-amino alkyl that then coupled with ubiquitous inexpensive (hetero)aryl chlorides. These coupling reactions require no oxidants or organometallic reagents, feature feedstock starting materials, broad substrate scope, high enantioselectivities, applicable late-stage diversification medicinally relevant complex molecules. Mechanistic studies suggest nickel catalyst uncommonly plays multiple roles, accomplishing radical generation, capture, cross-coupling, induction.

Language: Английский

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Desulfonylative Transformations of Sulfones by Transition-Metal Catalysis, Photocatalysis, and Organocatalysis

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(5), P. 3013 - 3032

Published: Feb. 18, 2022

Sulfones are common, readily available reagents that have recently attracted attention as versatile for cross-coupling reactions. This Review summarizes advances in desulfonylative transformations of sulfones affected by molecular catalysis, including transition-metal catalysts, photocatalysts, and organocatalysts. In addition to catalyst choice, the design sulfonyl group is a critical factor control reactivity. The concepts presented herein will provide new strategies construct diverse molecules with high efficiency modularity.

Language: Английский

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Multimetallic-Catalyzed C–C Bond-Forming Reactions: From Serendipity to Strategy

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(12), P. 6596 - 6614

Published: March 13, 2023

The use of two or more metal catalysts in a reaction is powerful synthetic strategy to access complex targets efficiently and selectively from simple starting materials. While capable uniting distinct reactivities, the principles governing multimetallic catalysis are not always intuitive, making discovery optimization new reactions challenging. Here, we outline our perspective on design elements using precedent well-documented C–C bond-forming reactions. These strategies provide insight into synergy compatibility individual components reaction. Advantages limitations discussed promote further development field.

Language: Английский

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