C–H Activation: Toward Sustainability and Applications

ACS Central Science, Год журнала: 2021, Номер 7(2), С. 245 - 261

Опубликована: Фев. 2, 2021

Since the definition of "12 Principles Green Chemistry" more than 20 years ago, chemists have become increasingly mindful need to conserve natural resources and protect environment through judicious choice synthetic routes materials. The direct activation functionalization C–H bonds, bypassing intermediate functional group installation is, in abstracto, step atom economic, but numerous factors still hinder sustainability large-scale applications. In this Outlook, we highlight research areas seeking overcome challenges activation: pursuit abundant metal catalysts, avoidance static directing groups, replacement oxidants, introduction bioderived solvents. We close by examining progress made subfield aryl borylation from its origins, highly efficient precious Ir-based systems, emerging 3d catalysts. future growth field will depend on industrial uptake, thus urge researchers strive toward sustainable activation.

Язык: Английский

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Metal-Catalyzed Intermolecular Hydrofunctionalization of Allenes: Easy Access to Allylic Structures via the Selective Formation of C–N, C–C, and C–O Bonds

Chemical Reviews, Год журнала: 2020, Номер 120(24), С. 13545 - 13598

Опубликована: Дек. 10, 2020

Following a strong regain of interest over the past 20 years in chemistry allenes, this "forgotten" family unsaturated molecules is undergoing renaissance. In context, metal-catalyzed hydrofunctionalization allenes nowadays one most studied transformations. The latter great because it opens way to produce selectively functionalized allylic structures. These motifs are important synthesis, particularly for formation asymmetric centers. Hydrofunctionalization also totally atom economical strategy, avoiding generation any waste, Compared main pathway obtain (aka Tsuji-Trost substitution), does not require prefunctionalization starting material with leaving group. This review presents state art exploration all existing transition methods allowing selective intermolecular N–H, C–H, and O–H nucleophiles or electrophiles.

Язык: Английский

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Weak-Coordination in C–H Bond Functionalizations Catalyzed by 3d Metals

ACS Catalysis, Год журнала: 2022, Номер 12(6), С. 3452 - 3506

Опубликована: Март 3, 2022

Transition-metal-catalyzed C–H bond functionalizations have had an enormous influence on organic synthesis in recent times. However, the use of low-abundance 4d and 5d metals is almost inevitable, they are high demand. This will be a cause concern, hence, it important to develop methods based 3d metals, which widely present Earth's crust. In this regard, metal catalysts or their precursors for catalysis, general, functionalizations, particular, has gained significant momentum The major development catalytic with been achieved predominantly strongly coordinating directing groups such as pyridyl, pyrimidinyl, pyrazolyl, 8-amino-quinolinyl groups. Thus, prefunctionalization substrates these necessary, contradicts step- atom-economy activation. commonly available functional aldehyde, ketone, carboxylic acid, amide, hydroxy, N-oxides loosely bind through weak-coordination. These weakly orient activate regioselectively without need preinstalled Although challenging, contemporary topic actively pursued by many researchers Through article, we provide comprehensive overview metal-catalyzed, coordinating, directing-group-enabled reported until March 2021.

Язык: Английский

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Replacement of Less-Preferred Dipolar Aprotic and Ethereal Solvents in Synthetic Organic Chemistry with More Sustainable Alternatives

Chemical Reviews, Год журнала: 2022, Номер 122(6), С. 6749 - 6794

Опубликована: Фев. 24, 2022

Dipolar aprotic and ethereal solvents comprise just over 40% of all organic utilized in synthetic organic, medicinal, process chemistry. Unfortunately, many the common "go-to" are considered to be "less-preferable" for a number environmental, health, safety (EHS) reasons such as toxicity, mutagenicity, carcinogenicity, or practical handling flammability volatility. Recent legislative changes have initiated implementation restrictions on use commonly employed dipolar dimethylformamide (DMF) N-methyl-2-pyrrolidinone (NMP), ethers 1,4-dioxane. Thus, with growing legislative, EHS, societal pressures, need identify implement alternative that greener, safer, more sustainable has never been greater. Within this review, ubiquitous nature is discussed respect physicochemical properties made them so appealing chemists. An overview current being imposed discussed. A variety alternative, garnered attention past decade then examined, case studies examples where less-preferable successfully replaced safer highlighted. Finally, general guidance solvent selection replacement included Supporting Information review.

Язык: Английский

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Efficient Benzylic C–H Bond Activation over Single-Atom Yttrium Supported on TiO₂ via Facilitated Molecular Oxygen and Surface Lattice Oxygen Activation

ACS Catalysis, Год журнала: 2023, Номер 14(1), С. 249 - 261

Опубликована: Дек. 14, 2023

Selective activation of C(sp3)–H bonds is important for value-added chemical production, but it remains challenging to proceed under moderate conditions. Herein, we report single-atom yttrium supported on TiO2 (Y1/TiO2) as a catalyst photocatalytic benzylic C–H bond at room temperature. In toluene oxidation, exhibits conversion rate 850 μmol g–1 h–1 with high benzaldehyde selectivity 94.1%. Experimental data show that abundant Y1δ+–O–Ti3+ (δ > 3) sites are formed the interface strong electronic metal–support interactions, inducing highly spin-polarized electrons facilitate charge separation. Furthermore, Y species promote formation oxygen vacancies and lead lattice distortion TiO2, which facilitates molecular surface activation. These reactive can directly react benzyl radical light irradiation produce hence increase performance. This work shows great potential rare-earth catalysts in mild conditions driven by renewable solar energy.

Язык: Английский

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Cobaltaelectro-Catalyzed C–H Annulation with Allenes for Atropochiral and P-Stereogenic Compounds: Late-Stage Diversification and Continuous Flow Scale-Up

ACS Catalysis, Год журнала: 2023, Номер 13(14), С. 9713 - 9723

Опубликована: Июль 11, 2023

The 3d metallaelectro-catalyzed C-H activation has been identified as an increasingly viable strategy to access valuable organic molecules in a resource-economic fashion under exceedingly mild reaction conditions. However, the development of enantioselective is very challenging and its infancy. Here, we disclose merger cobaltaelectro-catalyzed with asymmetric catalysis for highly annulation allenes. A broad range C-N axially chiral P-stereogenic compounds were thereby obtained good yields up 98% high enantioselectivities >99% ee. practicality this approach was demonstrated by diversification complex bioactive drug well decagram scale electrocatalysis continuous flow.

Язык: Английский

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Room temperature photo-promoted iron-catalysed arene C–H alkenylation without Grignard reagents

Nature Catalysis, Год журнала: 2024, Номер 7(3), С. 273 - 284

Опубликована: Фев. 13, 2024

Язык: Английский

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Heterogeneous Iron-Based Catalysts for Organic Transformation Reactions: A Brief Overview

Molecules, Год журнала: 2024, Номер 29(13), С. 3177 - 3177

Опубликована: Июль 3, 2024

Iron (Fe) is considered to be one of the most significant elements due its wide applications. Recent years have witnessed a burgeoning interest in Fe catalysis as sustainable and cost-effective alternative noble metal organic synthesis. The abundance low toxicity Fe, coupled with competitive reactivity selectivity, underscore appeal for A lot catalytic reactions been performed using heterogeneous catalysts oxide hybridized support systems like aluminosilicates, clays, carbonized materials, oxides or polymeric matrices. This review provides comprehensive overview latest advancements Fe-catalyzed transformation reactions. Highlighted areas include cross-coupling reactions, C-H activation, asymmetric catalysis, cascade processes, showcasing versatility across spectrum synthetic methodologies. Emphasis placed on mechanistic insights, elucidating underlying principles governing iron-catalyzed Challenges opportunities field are discussed, providing roadmap future research endeavors. Overall, this illuminates transformative potential driving innovation sustainability chemistry, implications drug discovery, materials science, beyond.

Язык: Английский

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Rh(iii)-Catalyzed [5 + 1] annulation of 2-alkenylanilides and 2-alkenylphenols with allenyl acetates

Chemical Science, Год журнала: 2022, Номер 13(7), С. 2043 - 2049

Опубликована: Янв. 1, 2022

A highly regioselective Rh( iii )-catalyzed non-oxidative [5 + 1] vinylic C–H annulation of 2-alkenylanilides and 2-alkenylphenols with allenyl acetates was described for accessing dihyroquinoline chromene derivatives.

Язык: Английский

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Chelation-Assisted Iron-Catalyzed C–H Activations: Scope and Mechanism

Accounts of Chemical Research, Год журнала: 2023, Номер 57(1), С. 10 - 22

Опубликована: Дек. 20, 2023

ConspectusTo improve the resource economy of molecular syntheses, researchers have developed strategies to directly activate otherwise inert C–H bonds, thus avoiding cumbersome and costly substrate prefunctionalizations. During past two decades, remarkable progress in coordination chemistry has set stage for developing increasingly viable metal catalysts activations. Despite advances, activations are largely dominated by precious 4d 5d transition based primarily on palladium, ruthenium, iridium, rhodium, decreasing inherent sustainable nature activation approach. Therefore, advancing catalytic reactions Earth-abundant less toxic 3d metals, especially nontoxic inexpensive iron, represents a desirable attractive alternative. While research had previously focused 8-aminoquinoline directing groups activations, we devised easily accessible, tunable, clickable triazoles, which feature widespread applications bioactive compounds drugs, among others, as peptide isosteres. Thus, contrast other groups, triazole group is highly structural motif functions bioisostere medicine biology, where it exploited mimic amide bonds.This Account summarizes evolution chelation-assisted iron-catalyzed via C–H, C–H/N–H, C–H/N–H/C–C bond cleavages, with topical focus most recent contributions our team. triazole-enabled iron catalysis surfaced transformative platform large variety transformations, including arylations, alkylations, alkenylations, allylations, annulations, alkynylations, achieved through organometallic reagents, organohalides, alkynes, alkenes, allenes, bicyclopropylidenes others. Consequently, widely applicable methods versatile preparation decorated arenes heteroarenes, providing access benzamides, isoquinolones, pyrrolones, pyridones, phenones, indoles, isoindolinones, Most these employed 1,2-dichloroisobutane (DCIB) an oxidant. Notably, chemical-oxidant-free were also developed, major breakthroughs being use internal oxidants oxidative resource-economic electrocatalysis, development well-defined iron(0)-mediated catalysis. In addition, enantioselective inner-sphere alkylation (aza)indoles was designing novel remotely N-heterocyclic carbene ligands dispersion energy donors. detailed mechanistic experiments kinetic analyses, intermediate isolation, Mößbauer spectroscopy, computation provided strong support mode operation, enabling unprecedented Thereby, low-valent paved way toward weakly coordinating ketones intermediates.

Язык: Английский

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