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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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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Metallaphotoredox-enabled deoxygenative arylation of alcohols

Nature, Journal Year: 2021, Volume and Issue: 598(7881), P. 451 - 456

Published: Aug. 31, 2021

Language: Английский

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Synthetic and Mechanistic Implications of Chlorine Photoelimination in Nickel/Photoredox C(sp³)–H Cross-Coupling

Accounts of Chemical Research, Journal Year: 2021, Volume and Issue: 54(4), P. 988 - 1000

Published: Jan. 29, 2021

ConspectusIn recent years, the development of light-driven reactions has contributed numerous advances in synthetic organic chemistry. A particularly active research area combines photoredox catalysis with nickel to accomplish otherwise inaccessible cross-coupling reactions. In these reactions, catalyst absorbs light generate an electronically excited charge-transfer state that can engage electron or energy transfer a substrate and catalyst. Our group questioned whether photoinduced activation itself could also contribute new approaches cross-coupling. Over past 5 we have sought advance this hypothesis for suite mild site-selective C(sp3)–H chloride-containing coupling partners via photoelimination Ni–Cl bond.On basis report from Nocera laboratory, reasoned photolysis Ni(III) aryl chloride species, generated by single-electron oxidation typical Ni(II) intermediate cross-coupling, might allow catalytic generation chlorine atoms. Combining ability accept alkyl radicals, hypothesized photocatalytically atoms mediate hydrogen atom (HAT) bonds substrate-derived radical is captured Ni center was envisioned promote necessary reduction facilitate overall redox-neutral process. Overall, strategy would offer visible-light-driven mechanism formation enabled sequential capture two photons.As initial demonstration, developed Ni/photoredox-catalyzed α-oxy arylation cyclic acyclic ethers. This method extended formylation abundant complex chlorides through selective 2-functionalization 1,3-dioxolane. Seeking develop introduce carbon at all different states, explored trimethyl orthoformate, common laboratory solvent. We found orthoformate serves as source methyl methylation reaction β-scission tertiary upon chlorine-mediated HAT. Since capable abstracting unactivated bonds, our efforts been directed range feedstock chemicals, such alkanes toluenes, along late-stage intermediates, using chloroformates partners. platform enables access valuable transformations (hetero)aryl chlorides, which despite being most ubiquitous inexpensive halide partners, are rarely reactive Ni/photoredox catalysis.Little known about photophysics photochemistry organometallic complexes relevant conducted mechanistic investigations, including computational, spectroscopic, emission quenching, stoichiometric studies, These studies indicate operative described functionalization methods. More generally, illustrate catalysts cannot be ignored metallaphotoredox anticipate further understanding should design lead

Language: Английский

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General Method for Enantioselective Three-Component Carboarylation of Alkenes Enabled by Visible-Light Dual Photoredox/Nickel Catalysis

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(48), P. 20390 - 20399

Published: Nov. 19, 2020

A visible-light-promoted photoredox/nickel protocol for the enantioselective three-component carboarylation of alkenes with tertiary and secondary alkyltrifluoroborates aryl bromides is described. This redox-neutral allows facile divergent access to a wide array enantioenriched β-alkyl-α-arylated carbonyls, phosphonates, sulfones in high yields excellent enantioselectivities from readily available starting materials. We also report modular synthesis flurbiprofen analogs piragliatin lead compound demonstrate synthetic utility. Experimental computational mechanistic studies were performed gain insights into mechanism origin chemo- enantioselectivity.

Language: Английский

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Nickel-catalyzed formation of quaternary carbon centers using tertiary alkyl electrophiles

Chemical Society Reviews, Journal Year: 2021, Volume and Issue: 50(6), P. 4162 - 4184

Published: Jan. 1, 2021

This review provides a comprehensive summary of recent advances in nickel-catalyzed reactions employing tertiary alkyl electrophiles for the construction quaternary carbon centers.

Language: Английский

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Nontraditional Fragment Couplings of Alcohols and Carboxylic Acids: C(sp³)–C(sp³) Cross-Coupling via Radical Sorting

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(14), P. 6185 - 6192

Published: March 30, 2022

Alcohols and carboxylic acids are among the most commercially abundant, synthetically versatile, operationally convenient functional groups in organic chemistry. Under visible light photoredox catalysis, these native synthetic handles readily undergo radical activation, resulting open-shell intermediates can subsequently participate transition metal catalysis. In this report, we describe C(sp3)–C(sp3) cross-coupling of alcohols through dual combination N-heterocyclic carbene (NHC)-mediated deoxygenation hypervalent iodine-mediated decarboxylation. This mild practical Ni-catalyzed radical-coupling protocol was employed to prepare a wide array alkyl–alkyl cross-coupled products, including highly congested quaternary carbon centers from corresponding tertiary or acids. We demonstrate applications methodology alcohol C1-alkylation formal homologation, as well late-stage functionalization drugs, natural biomolecules.

Language: Английский

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Photochemical C–H Activation Enables Nickel-Catalyzed Olefin Dicarbofunctionalization

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(10), P. 3901 - 3910

Published: March 4, 2021

Alkenes, ethers, and alcohols account for a significant percentage of bulk reagents available to the chemistry community. The petrochemical, pharmaceutical, agrochemical industries each consume gigagrams these materials as fuels solvents year. However, utilization such building blocks construction complex small molecules is limited by necessity prefunctionalization achieve chemoselective reactivity. Herein, we report implementation efficient, sustainable, diaryl ketone hydrogen-atom transfer (HAT) catalysis activate native C–H bonds multicomponent dicarbofunctionalization alkenes. ability forge new carbon–carbon between typically viewed commodity provides new, more atom-economic outlook organic synthesis. Through detailed experimental computational investigation, critical effect hydrogen bonding on reactivity this transformation was uncovered.

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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Ni/Photoredox-Catalyzed Enantioselective Cross-Electrophile Coupling of Styrene Oxides with Aryl Iodides

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(38), P. 15873 - 15881

Published: Sept. 20, 2021

A Ni/photoredox-catalyzed enantioselective reductive coupling of styrene oxides and aryl iodides is reported. This reaction affords access to enantioenriched 2,2-diarylalcohols from racemic epoxides via a stereoconvergent mechanism. Multivariate linear regression (MVLR) analysis with 29 bioxazoline (BiOx) biimidazoline (BiIm) ligands revealed that enantioselectivity correlates electronic properties the ligands, more electron-donating affording higher ee's. Experimental computational mechanistic studies were conducted, lending support hypothesis elimination enantiodetermining character influences by altering position transition state structure along coordinate. study demonstrates benefits utilizing statistical modeling as platform for understanding provides new insight into an emerging class chiral Ni Ni/photoredox cross-coupling.

Language: Английский

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