3d Transition Metals for C–H Activation

Chemical Reviews, Год журнала: 2018, Номер 119(4), С. 2192 - 2452

Опубликована: Ноя. 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.

Язык: Английский

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Electrocatalysis as an enabling technology for organic synthesis

Chemical Society Reviews, Год журнала: 2021, Номер 50(14), С. 7941 - 8002

Опубликована: Янв. 1, 2021

Electrochemistry has recently gained increased attention as a versatile strategy for achieving challenging transformations at the forefront of synthetic organic chemistry. Electrochemistry's unique ability to generate highly reactive radical and ion intermediates in controlled fashion under mild conditions inspired development number new electrochemical methodologies preparation valuable chemical motifs. Particularly, recent developments electrosynthesis have featured an use redox-active electrocatalysts further enhance control over selective formation downstream reactivity these intermediates. Furthermore, electrocatalytic mediators enable proceed manner that is mechanistically distinct from purely methods, allowing subversion kinetic thermodynamic obstacles encountered conventional synthesis. This review highlights key innovations within past decade area electrocatalysis, with emphasis on mechanisms catalyst design principles underpinning advancements. A host oxidative reductive are discussed grouped according classification transformation nature electrocatalyst.

Язык: Английский

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Recent Advances in Oxidative R¹-H/R²-H Cross-Coupling with Hydrogen Evolution via Photo-/Electrochemistry

Chemical Reviews, Год журнала: 2019, Номер 119(12), С. 6769 - 6787

Опубликована: Май 10, 2019

Photo-/electrochemical catalyzed oxidative R1-H/R2-H cross-coupling with hydrogen evolution has become an increasingly important issue for molecular synthesis. The dream of construction C-C/C-X bonds from readily available C-H/X-H release H2 can be facilely achieved without external chemical oxidants, providing a greener model bond formation. Given the great influence these reactions in organic chemistry, we give summary state art via photo/electrochemistry, and hope this review will stimulate development synthetic strategy near future.

Язык: Английский

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Electrochemical Oxidative Cross-Coupling with Hydrogen Evolution Reactions

Accounts of Chemical Research, Год журнала: 2019, Номер 52(12), С. 3309 - 3324

Опубликована: Ноя. 27, 2019

Oxidative cross-coupling has proved to be one of the most straightforward strategies for forming carbon-carbon and carbon-heteroatom bonds from easily available precursors. Over past two decades, tremendous efforts have been devoted in this field significant advances achieved. However, order remove surplus electrons substrates chemical formation, stoichiometric oxidants are usually needed. Along with development modern sustainable chemistry, considerable perform oxidative reactions under external-oxidant-free conditions. Electrochemical synthesis is a powerful environmentally benign approach, which can not only achieve cross-couplings conditions, but also release valuable hydrogen gas during bond formation. Recently, electrochemical evolution significantly explored. This Account presents our recent toward reactions. (1) We explored thiols/thiophenols arenes, heteroarenes, alkenes C-S (2) Using strategy C-H/N-H evolution, we successfully realized C-H amination phenols, anilines, imidazopyridines, even ethers. (3) Employing halide salts as green halogenating reagents, developed clean halogenation protocol oxidation To address limitation that reaction had carry out aqueous solvent, an alternative method uses CBr4, CHBr3, CH2Br2, CCl3Br, CCl4 reagents mixture acetonitrile methanol cosolvent. (4) approach constructing C-O well-developed manner. (5) Under mild C(sp2)-H C(sp3)-H phosphonylation modest high yields. (6) achieved S-H/S-H By anodic instead oxidants, overoxidation thiols thiophenols was well avoided. (7) The methods structurally diverse heterocyclic compounds were via annulations. (8) applied difunctionalization multiple step, such C-S/C-O bonds, C-S/C-N C-Se/C-O C-Se/C-N bonds. hope studies will stimulate research interest chemists pave way discovery more

Язык: Английский

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Site-Selective C–H Functionalization via Synergistic Use of Electrochemistry and Transition Metal Catalysis

Accounts of Chemical Research, Год журнала: 2020, Номер 53(2), С. 300 - 310

Опубликована: Янв. 15, 2020

Electrochemical synthesis of organic compounds has emerged as an attractive and environmentally benign alternative to conventional approaches for oxidation reduction that utilizes electric current instead chemical oxidants reductants. As such, many useful transformations have been developed, including the Kolbe reaction, Simons fluorination process, Monsanto adiponitrile Shono oxidation, name a few. C-H functionalization represents one most promising reaction types among electrochemical transformations, since this process avoids prefunctionalization substrates provides novel retrosynthetic disconnections. However, site-selective anodic bonds is still fundamental challenge due high potentials compared solvents common functional groups. To overcome issue, indirect electrolysis via action mediator (a redox catalyst) regularly employed, by which selectivity can be controlled following said with substrate. Since transition metal complexes easily tuned modification ligand, synergistic use electrochemistry catalysis achieve strategy. In Account, we summarize contextualize our recent efforts toward metal-catalyzed proximal suitable directing group. We developed oxygenation, acylation, alkylation, halogenation reactions in Pd(II) species oxidized Pd(III) or Pd(IV) intermediate followed reductive elimination form corresponding C-O, C-C, C-X bonds. Importantly, improved monofunctionalization achieved Pd-catalyzed C(sp3)-H oxygenation using PhI(OAc)2 oxidant. Physical separators are sometimes used prevent deposition Pd black on cathode resulting from valent species. skirted issue through development Cu-catalyzed C(sp2)-H amination n-Bu4NI cocatalyst undivided cell. addition, Ir-catalyzed vinylic acrylic acids alkynes cell, affording various substituted α-pyrones good excellent yield. More importantly, oxidants, Ag2CO3, Cu(OAc)2, PhI(OAc)2, resulted much lower yields absence electrical under otherwise identical conditions. elaborated below, progress area effective platform friendly sustainable selective transformations.

Язык: Английский

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Metalla-electrocatalyzed C–H Activation by Earth-Abundant 3d Metals and Beyond

Accounts of Chemical Research, Год журнала: 2019, Номер 53(1), С. 84 - 104

Опубликована: Дек. 19, 2019

To improve the efficacy of molecular syntheses, researchers wish to capitalize upon selective modification otherwise inert C-H bonds. The past two decades have witnessed considerable advances in coordination chemistry that set stage for transformative tools functionalizations. Particularly, oxidative C-H/C-H and C-H/Het-H transformations gained major attention because they avoid all elements substrate prefunctionalization. Despite advances, activations been dominated by precious transition metal catalysts based on palladium, ruthenium, iridium, rhodium, thus compromising sustainable nature overall activation approach. same holds true predominant use stoichiometric chemical oxidants regeneration active catalyst, prominently featuring hypervalent iodine(III), copper(II), silver(I) oxidants. Thereby, quantities undesired byproducts are generated, which preventive applications scale. In contrast, elegant merger homogeneous metal-catalyzed with electrosynthesis bears unique power achieve outstanding levels oxidant resource economy. Thus, contrast classical electrosyntheses control, metalla-electrocatalysis huge largely untapped potential unmet site selectivities means catalyst control. While indirect electrolysis using palladium complexes has realized, less toxic expensive base feature distinct beneficial assets toward this Account, I summarize emergence electrocatalyzed earth-abundant 3d metals beyond, a topical focus contributions from our laboratories through November 2019. cobalt electrocatalysis was identified as particularly powerful platform wealth transformations, including oxygenations nitrogenations well alkynes, alkenes, allenes, isocyanides, carbon monoxide, among others. As complementary tools, nickel, copper, very recently iron devised metalla-electrocatalyzed activations. Key success were detailed mechanistic insights, oxidation-induced reductive elimination scenarios. Likewise, development methods make weak O-coordination benefited crucial insights into catalyst's modes action experiment, operando spectroscopy, computation. Overall, thereby syntheses These electrooxidative frequently characterized improved chemoselectivities. Hence, ability dial redox at minimum level required desired transformation renders an ideal functionalization structurally complex molecules sensitive functional groups. This strategy was, inter alia, successfully applied scale-up continuous flow step-economical assembly polycyclic aromatic hydrocarbons.

Язык: Английский

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C–H activation

Nature Reviews Methods Primers, Год журнала: 2021, Номер 1(1)

Опубликована: Июнь 17, 2021

Язык: Английский

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Recent Developments for the Deuterium and Tritium Labeling of Organic Molecules

Chemical Reviews, Год журнала: 2022, Номер 122(6), С. 6634 - 6718

Опубликована: Фев. 18, 2022

Organic compounds labeled with hydrogen isotopes play a crucial role in numerous areas, from materials science to medicinal chemistry. Indeed, while the replacement of by deuterium gives rise improved absorption, distribution, metabolism, and excretion (ADME) properties drugs enables preparation internal standards for analytical mass spectrometry, use tritium-labeled is key technique all along drug discovery development pharmaceutical industry. For these reasons, interest new methodologies isotopic enrichment organic molecules extent their applications are equally rising. In this regard, Review intends comprehensively discuss developments area over last years (2017–2021). Notably, besides fundamental isotope exchange (HIE) reactions isotopically analogues common reagents, plethora reductive dehalogenative deuteration techniques other transformations incorporation emerging now part labeling toolkit.

Язык: Английский

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A synthetic chemist's guide to electroanalytical tools for studying reaction mechanisms

Chemical Science, Год журнала: 2019, Номер 10(26), С. 6404 - 6422

Опубликована: Янв. 1, 2019

A range of electroanalytical tools can be applied to studying redox reactions, probing key mechanistic questions in synthetic chemistry.

Язык: Английский

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New Redox Strategies in Organic Synthesis by Means of Electrochemistry and Photochemistry

ACS Central Science, Год журнала: 2020, Номер 6(8), С. 1317 - 1340

Опубликована: Июль 16, 2020

As the breadth of radical chemistry grows, new means to promote and regulate single-electron redox activities play increasingly important roles in driving modern synthetic innovation. In this regard, photochemistry electrochemistry-both considered as niche fields for decades-have seen an explosive renewal interest recent years gradually have become a cornerstone organic chemistry. Outlook article, we examine current state-of-the-art areas electrochemistry photochemistry, well nascent area electrophotochemistry. These techniques employ external stimuli activate molecules imbue privileged control reaction progress selectivity that is challenging traditional chemical methods. Thus, they provide alternative entries known reactive intermediates enable distinct strategies were previously unimaginable. Of many hallmarks, electro- are often classified "green" technologies, promoting reactions under mild conditions without necessity potent wasteful oxidants reductants. This reviews most growth these with special emphasis on conceptual advances given rise enhanced accessibility tools trade.

Язык: Английский

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