3d Transition Metals for C–H Activation

Chemical Reviews, Journal Year: 2018, Volume and Issue: 119(4), P. 2192 - 2452

Published: Nov. 27, 2018

C–H activation has surfaced as an increasingly powerful tool for molecular sciences, with notable applications to material crop protection, drug discovery, and pharmaceutical industries, among others. Despite major advances, the vast majority of these functionalizations required precious 4d or 5d transition metal catalysts. Given cost-effective sustainable nature earth-abundant first row metals, development less toxic, inexpensive 3d catalysts gained considerable recent momentum a significantly more environmentally-benign economically-attractive alternative. Herein, we provide comprehensive overview on until summer 2018.

Language: Английский

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Electrochemical strategies for C–H functionalization and C–N bond formation

Chemical Society Reviews, Journal Year: 2018, Volume and Issue: 47(15), P. 5786 - 5865

Published: Jan. 1, 2018

This review provides an overview of the use electrochemistry as appealing platform for expediting carbon–hydrogen functionalization and carbon–nitrogen bond formation.

Language: Английский

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Visible Light-Driven Radical-Mediated C–C Bond Cleavage/Functionalization in Organic Synthesis

Chemical Reviews, Journal Year: 2020, Volume and Issue: 121(1), P. 506 - 561

Published: May 29, 2020

Thermal C–C bond cleavage reactions allow the construction of structurally diverse molecular skeletons via predictable and efficient reorganizations. Visible light photoredox-catalyzed radical-mediated have recently emerged as a powerful alternative method for overcoming thermodynamic kinetic barrier in scaffolds. In recent years, plethora elegant useful been invented, products are sometimes otherwise inaccessible by classic thermal reactions. Considering great influence synthetic potential these reactions, we provide summary state art visible light-driven cleavage/functionalization strategies with specific emphasis on working models. We hoped that this review will be medicinal organic chemists inspire further reaction development interesting area.

Language: Английский

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Bidentate Directing Groups: An Efficient Tool in C–H Bond Functionalization Chemistry for the Expedient Construction of C–C Bonds

Chemical Reviews, Journal Year: 2020, Volume and Issue: 120(3), P. 1788 - 1887

Published: Jan. 6, 2020

During the past decades, synthetic organic chemistry discovered that directing group assisted C–H activation is a key tool for expedient and siteselective construction of C–C bonds. Among various strategies, bidentate groups are now recognized as one most efficient devices selective functionalization certain positions due to fact its metal center permits fine, tunable, reversible coordination. The family permit types assistance be achieved, such N,N-dentate, N,O-dentate, N,S-dentate auxiliaries, which categorized based on coordination site. In this review, we broadly discuss bond reactions formation bonds with aid groups.

Language: Английский

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Cooperative Coupling of Oxidative Organic Synthesis and Hydrogen Production over Semiconductor-Based Photocatalysts

Chemical Reviews, Journal Year: 2021, Volume and Issue: 121(21), P. 13051 - 13085

Published: Aug. 11, 2021

Merging hydrogen (H2) evolution with oxidative organic synthesis in a semiconductor-mediated photoredox reaction is extremely attractive because the clean H2 fuel and high-value chemicals can be coproduced under mild conditions using light as sole energy input. Following this dual-functional photocatalytic strategy, dreamlike pathway for constructing C–C/C–X (X = C, N, O, S) bonds from abundant readily available X–H bond-containing compounds concomitant release of fulfilled without need external chemical reagents, thus offering green fascinating synthetic strategy. In review, we begin by presenting concise overview on general background traditional production then focus fundamental principles cooperative coupling selective simultaneous utilization photoexcited electrons holes over semiconductor-based catalysts to meet economic sustainability goal. Thereafter, put dedicated emphasis recent key progress various transformations, including alcohol oxidation, methane conversion, amines coupling, cross-coupling, cyclic alkanes dehydrogenation, reforming lignocellulosic biomass, so on. Finally, remaining challenges future perspectives flourishing area have been critically discussed. It anticipated that review will provide enlightening guidance rational design such system, thereby stimulating development economical environmentally benign solar generation value-added fine chemicals.

Language: Английский

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Remote C–H Functionalization via Selective Hydrogen Atom Transfer

Synthesis, Journal Year: 2018, Volume and Issue: 50(08), P. 1569 - 1586

Published: Feb. 12, 2018

The selective functionalization of remote C–H bonds via intramolecular hydrogen atom transfer (HAT) is transformative for organic synthesis. This radical-mediated strategy provides access to novel reactivity that complementary closed-shell pathways. As modern methods mild generation radicals are continually developed, inherent selectivity paradigms HAT mechanisms offer unparalleled opportunities developing new strategies functionalization. review outlines the history, recent advances, and mechanistic underpinnings as a guide addressing ongoing challenges in this arena. 1 Introduction 2 Nitrogen-Centered Radicals 2.1 sp3 N-Radical Initiation 2.2 sp2 3 Oxygen-Centered 3.1 Carbonyl Diradical 3.2 Alkoxy Radical 3.3 Non-alkoxy 4 Carbon-Centered 4.1 C-Radical 4.2 5 Conclusion

Language: Английский

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Site-Selective C–H Functionalization by Decatungstate Anion Photocatalysis: Synergistic Control by Polar and Steric Effects Expands the Reaction Scope

ACS Catalysis, Journal Year: 2017, Volume and Issue: 8(1), P. 701 - 713

Published: Dec. 5, 2017

The synergistic control of the SH2 transition states hydrogen abstraction by polar and steric effects provides a promising strategy in achieving site-selective C(sp3)–H functionalization under decatungstate anion photocatalysis. By using this photocatalytic approach, C–H bonds alkanes, alcohols, ethers, ketones, amides, esters, nitriles, pyridylalkanes were functionalized site-selectively. In remarkable case 2,4-disubstituted cyclohexanone bearing five methyl, methylene, three methine bonds, one bond isoamyl tether was selectively functionalized.

Language: Английский

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A radical approach to the copper oxidative addition problem: Trifluoromethylation of bromoarenes

Science, Journal Year: 2018, Volume and Issue: 360(6392), P. 1010 - 1014

Published: June 1, 2018

Transition metal-catalyzed arene functionalization has been widely used for molecular synthesis over the past century. In this arena, copper catalysis long considered a privileged platform due to propensity of high-valent undergo reductive elimination with wide variety coupling fragments. However, sluggish nature oxidative addition limited copper's capacity broadly facilitate haloarene protocols. Here, we demonstrate that problem can be overcome an aryl radical-capture mechanism, wherein radical is generated through silyl halogen abstraction. This strategy was applied general trifluoromethylation bromides dual copper-photoredox catalysis. Mechanistic studies support formation open-shell species.

Language: Английский

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A Decade of Electrochemical Dehydrogenative C,C-Coupling of Aryls

Accounts of Chemical Research, Journal Year: 2019, Volume and Issue: 53(1), P. 45 - 61

Published: Dec. 18, 2019

The importance of sustainable and green synthetic protocols for the synthesis fine chemicals has rapidly increased during last decades in an effort to reduce use fossil fuels other finite resources. replacement common reagents by electricity provides a cost- atom-efficient, environmentally friendly, inherently safe access novel routes. selective formation carbon-carbon bonds between two distinct substrates is crucial tool organic chemistry. This fundamental transformation enables broad variety complex molecular architectures. In particular, aryl-aryl bond high significance preparation materials, drugs, natural products. Besides well-known well-established reductive- oxidative-reagent-mediated or transition-metal-catalyzed coupling reactions, have arisen, which require fewer steps than conventional approaches. Electroorganic conversions can be categorized according nature electron transfer processes occurring. Direct transformations at inert electrode materials are benign cost-effective, whereas catalytic active electrodes mediated electrosynthesis using additional soluble reagent beneficial properties terms selectivity reactivity. general, these challenging optimization reaction parameters appropriate cell design. Galvanostatic reactions enable fast with rather simple setup, potentiostatic electrolysis may enhance selectivity. Account discusses development seminal formations over past decades, focusing on phenols leading precursors ligands in, e.g., hydroformylation reaction. A key element success electrochemical application electrochemically inert, non-nucleophilic, highly fluorinated alcohols such as 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), exhibit large potential window cross-coupling reactions. based capability HFIP stabilize radicals. Inert, carbon-based metal-free like graphite boron-doped diamond (BDD) open up electroorganic pathways. Furthermore, been developed intra- intermolecular dehydrogenative electron-rich aryls. 2,2'-biphenol derivatives ligand components catalysts requires carried out larger scale. order achieve this, continuous flow established overcome drawbacks heat transfer, overconversion, conductivity. Modular designs into processes. Recent results demonstrate electrochemistry product pharmaceutically relevant opiate alkaloids (-)-thebaine (-)-oxycodone.

Language: Английский

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Enantioselective C−H Activation with Earth‐Abundant 3d Transition Metals

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(37), P. 12803 - 12818

Published: May 11, 2019

Molecular syntheses largely rely on time- and labour-intensive prefunctionalization strategies. In contrast, C-H activation represents an increasingly powerful approach that avoids lengthy of prefunctionalized substrates, with great potential for drug discovery, the pharmaceutical industry, material sciences, crop protection, among others. The enantioselective functionalization omnipresent bonds has emerged as a transformative tool step- atom-economical generation chiral molecular complexity. However, this rapidly growing research area remains dominated by noble transition metals, prominently featuring toxic palladium, iridium rhodium catalysts. Indeed, despite significant achievements, use inexpensive sustainable 3d metals in asymmetric activations is still clearly its infancy. Herein, we discuss remarkable recent progress transformations via organometallic base up to April 2019.

Language: Английский

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