Mechanisms of Photoredox Catalysis Featuring Nickel–Bipyridine Complexes

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(11), P. 9055 - 9076

Published: May 29, 2024

Metallaphotoredox catalysis can unlock useful pathways for transforming organic reactants into desirable products, largely due to the conversion of photon energy chemical potential drive redox and bond transformation processes. Despite importance these processes cross-coupling reactions other transformations, their mechanistic details are only superficially understood. In this review, we have provided a detailed summary various photoredox mechanisms that been proposed date Ni-bipyridine (bpy) complexes, focusing separately on photosensitized direct excitation reaction By highlighting multiple key findings, depict how mechanisms, which ultimately define substrate scope, themselves defined by ground- excited-state geometric electronic structures Ni-based intermediates. We further identify knowledge gaps motivate future studies development synergistic research approaches spanning physical, organic, inorganic chemistry communities.

Language: Английский

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Ni-Catalyzed Enantioselective Desymmetrization: Development of Divergent Acyl and Decarbonylative Cross-Coupling Reactions

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

Published: Jan. 14, 2025

Ni-catalyzed asymmetric reductive cross-coupling reactions provide rapid and modular access to enantioenriched building blocks from simple electrophile precursors. Reductive coupling that can diverge through a common organometallic intermediate two distinct families of products are particularly versatile but underdeveloped. Here, we describe the development bis(oxazoline) ligand enables desymmetrization meso-anhydrides. When secondary benzylic electrophiles employed, doubly stereoselective acyl proceeds give ketone with catalyst control over three newly formed stereogenic centers. Alternatively, use primary alkyl halides in presence an additional halogen atom transfer results decarbonylative alkylation β-alkyl acids. Analysis reaction rates for range both catalysts substrates supports notion tuning different activation steps is required enhanced performance. These studies illustrate how design Ni-acyl either or highlight dual systems be used engage unactivated coupling.

Language: Английский

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Recent Advances in Asymmetric Organometallic Electrochemical Synthesis (AOES)

Accounts of Chemical Research, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 19, 2025

ConspectusIn recent years, our research group has dedicated significant effort to the field of asymmetric organometallic electrochemical synthesis (AOES), which integrates electrochemistry with transition metal catalysis. On one hand, we have rationalized that compounds can serve as molecular electrocatalysts (mediators) reduce overpotentials and enhance both reactivity selectivity reactions. other conditions for catalysis be substantially improved through electrochemistry, enabling precise modulation metal's oxidation state by controlling potentials regulating electron transfer rate via current adjustments. This synergistic approach addresses key challenges inherent in traditional catalysis, particularly those related use redox-active chemical reagents. Furthermore, redox conveniently tuned modifying their ligands, thereby governing reaction regioselectivity stereoselectivity. As a result, AOES emerged powerful promising tool chiral compounds.In this Account, summarize contextualize efforts AOES. Our primary strategy involves leveraging controllability potential regulate organometallics, facilitating desired An efficient platform was established under mild conditions, significantly reducing reliance on been systematically categorized into three sections based distinct electrolysis modes: combined anodic oxidation, cathodic reduction, paired electrolysis. In each section, highlight innovative discoveries tailored unique characteristics respective modes.In many transformations, metal-catalyzed reactions involving reagents utilizing exhibit similar reactivities. However, also observed notable differences certain cases. These findings include following: (1) Enhanced efficiency synthesis: instance, Rh-catalyzed enantioselective functionalization C–H bonds demonstrates superior efficiency. (2) Expanded scope transformations: previously challenging achieved due tunability potentials. A example is reductive coupling aryl chlorides, expands range accessible transformations. Additionally, mechanistic studies explore techniques intrinsic such controlled experiments, impact electrode materials catalyst performance, cyclic voltammetry studies. investigations provide more intuitive understanding behavior catalysts study mechanisms, guide design new catalytic systems.The advancements offer robust environmentally friendly sustainable selective By integrating developed versatile organic not only enhances but reduces environmental impact. We anticipate Account will stimulate further innovation realm AOES, leading discovery systems development synthetic methodologies.

Language: Английский

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Enantioselective Alkyl–Acyl Radical Cross-Coupling Enabled by Metallaphotoredox Catalysis

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

Published: Feb. 19, 2025

Radical-radical cross-coupling (RCC) offers a promising approach for carbon-carbon bond formation in organic synthesis, particularly creating complex, three-dimensional molecules. However, achieving both cross- and enantioselectivity RCC reactions has remained significant challenge. Here, we report novel metallaphotoredox platform that enables highly enantioselective decarboxylative coupling of carboxylic acid derivatives with aldehydes. Our strategy leverages independent control over radical generation subsequent through fine-tuning common photocatalyst simple chiral bis(oxazoline) nickel catalyst. This redox-neutral protocol requires no exogenous oxidants or reductants demonstrates broad substrate scope functional group compatibility the synthesis enantioenriched α-aryl α-amino ketones. The ketone products can be readily transformed into valuable β-amino alcohols, streamlining access to these important motifs. Furthermore, showcase potential this more challenging C(sp3)-C(sp3) alkyl-alkyl reactions. unified alkyl-acyl represents advance asymmetric catalysis underscores exploit new mechanisms solve long-standing synthetic problems.

Language: Английский

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Nickel-Catalyzed Enantioselective Reductive Arylation of Common Ketones

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(19), P. 12895 - 12900

Published: May 2, 2024

A nickel complex of chiral bisoxazolines catalyzed the stereoselective reductive arylation ketones in high enantioselectivity. range common acyclic and cyclic reacted without aid directing groups. Mechanistic studies using isolated a bis(oxazoline) (L)Ni(Ar)Br revealed that Mn reduction was not needed, while Lewis acidic titanium alkoxides were critical to ketone insertion.

Language: Английский

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Enantioselective reductive cross-couplings to forge C(sp2)–C(sp3) bonds by merging electrochemistry with nickel catalysis

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: Jan. 28, 2025

Abstract Motivated by the inherent benefits of synergistically combining electrochemical methodologies with nickel catalysis, we present here a Ni-catalyzed enantioselective electroreductive cross-coupling benzyl chlorides aryl halides, yielding chiral 1,1-diaryl compounds good to excellent enantioselectivity. This catalytic reaction can not only be applied chlorides/bromides, which are challenging access other means, but also containing silicon groups. Additionally, absence sacrificial anode lays foundation for scalability. The combination cyclic voltammetry analysis electrode potential studies suggests that Ni I species activate halides via oxidative addition and alkyl single electron transfer.

Language: Английский

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Dual Nickel- and Photoredox-Catalyzed Asymmetric Reductive Cross-Couplings: Just a Change of the Reduction System?

Accounts of Chemical Research, Journal Year: 2024, Volume and Issue: 57(14), P. 1997 - 2011

Published: July 4, 2024

ConspectusIn recent years, nickel-catalyzed asymmetric coupling reactions have emerged as efficient methods for constructing chiral C(sp

Language: Английский

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Nickel-Catalyzed Atroposelective Cross-Electrophile Coupling of Aryl Halides: A General and Practical Route to Diverse MOP-Type Ligands

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(26), P. 17606 - 17612

Published: May 23, 2024

We report a highly cross- and atroposelective coupling between ortho-(chloro)arylphosphine oxides ortho-(bromo)aryl ethers. This previously unknown asymmetric nickel-catalyzed reaction offers direct route to enantioenriched axially chiral biaryl monophosphine that are difficult access by other means. These products can be readily reduced generate MOP-type ligands bearing complex skeletal backbones. The utility of these in catalysis is also demonstrated.

Language: Английский

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Reductive Cyclopropanation through Bismuth Photocatalysis

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(32), P. 22140 - 22144

Published: Aug. 5, 2024

We present here a catalytic method based on low-valent Bi complex capable of cyclopropanation double bonds under blue LED irradiation. The catalysis features various unusual Bi-based organometallic steps, namely, (1) two-electron inner sphere oxidative addition Bi(I) to CH2I2, (2) light-induced homolysis the Bi(III)–CH2I bond, (3) subsequent iodine abstraction-ring-closing, and (4) reduction Bi(III) with an external reducing agent close cycle. Stoichiometric experiments support proposed mechanism. This protocol represents unique example reductive photocatalytic process bismuth radical catalysis.

Language: Английский

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Nickel-Catalyzed Enantioselective C(sp³)–C(sp³) Cross-Electrophile Coupling of N-Sulfonyl Styrenyl Aziridines with Alkyl Bromides

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(37), P. 25426 - 25432

Published: Sept. 4, 2024

Herein, we report the first example of a highly enantioselective alkylative aziridine ring opening. Under catalysis chiral nickel/pyridine-imidazoline complex, asymmetric C(sp

Language: Английский

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