Close‐Shell Reductive Elimination versus Open‐Shell Radical Coupling for Site‐Selective Ruthenium‐Catalyzed C−H Activations by Computation and Experiments

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(22)

Published: Feb. 27, 2023

Ruthenium-catalyzed σ-bond activation-assisted meta-C-H functionalization has emerged as a useful tool to forge distal C-C bonds. However, given the limited number of mechanistic studies, clear understanding origin site-selectivity and complete reaction pattern is not available. Here, we present systematic computational studies on ruthenium-catalyzed C-H with primary, secondary, tertiary alkyl bromides aryl bromides. The scission formation were carefully examined. Monocyclometalated ruthenium(II) complexes identified active species, which then underwent inner-sphere single electron transfer (ISET) activate organic results from competition between close-shell reductive elimination open-shell radical coupling. Based this understanding, multilinear regression model was built predict site-selectivity, further validated by experiments.

Language: Английский

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meta-Selective O-Arylation of Cyclic Diaryliodonium Salts with Phenols via Aryne Intermediates

Organic Letters, Journal Year: 2023, Volume and Issue: 25(16), P. 2777 - 2781

Published: April 14, 2023

Herein, we report a base-mediated, highly meta-selective O-arylation process of phenols and cyclic diaryliodonium salts without usage transition metals. This novel practical method was proved to be useful for the synthesis iodine-containing meta-functionalized biaryl ethers in broad functional group tolerance environmentally friendly manner. Diversity-oriented transformations products were carried out give various valuable functionalized biaryls. Preliminary mechanistic studies support proposed aryne generation mechanism.

Language: Английский

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Visible-Light-Mediated Ruthenium-Catalyzed para-Selective Alkylation of Unprotected Anilines

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(11), P. 7310 - 7321

Published: May 15, 2023

Anilines are important moieties in organic chemistry, pharmaceuticals, and materials science. Although para-selective functionalization of anilides tertiary anilines is well established, unprotected have posed a challenge. Herein, we report visible-light-mediated Ru(II)-catalyzed para-alkylation anilines. The distinct Ru(II)–aniline complex enabled the reaction to proceed with extremely high efficiency (2 h) under mild conditions. good functional group tolerance allowed late-stage even aggregation-induced emission luminogen labeling natural products drugs. A mechanistic investigation suggests that crucial for both triggering controlling para-selectivity.

Language: Английский

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Transition Metal‐Catalyzed C−H Functionalization Through Electrocatalysis

ChemSusChem, Journal Year: 2023, Volume and Issue: 16(12)

Published: March 7, 2023

Electrochemically promoted transition metal-catalyzed C-H functionalization has emerged as a promising area of research over the last few decades. However, development in this field is still at an early stage compared to traditional reactions using chemical-based oxidizing agents. Recent reports have shown increased attention on electrochemically functionalization. From standpoint sustainability, environmental friendliness, and cost effectiveness, oxidation metal catalyst offers mild, efficient, atom-economical alternative chemical oxidants. This Review discusses advances metal-electrocatalyzed past decade describes how unique features electricity enable economic sustainable way.

Language: Английский

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Relay C–H Functionalization Enables De Novo Synthesis of Pyridines and Pyridones

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(9), P. 5795 - 5807

Published: April 13, 2023

The realization of sequential and controllable C–H functionalization in one step can maximize the utilization bonds to rapidly create valuable scaffolds dramatically increase atom functional group utilization. In this work, we describe an iron-catalyzed relay proto col that enables de novo synthesis a wide range pyridines pyridones. This transformation involves three-fold (two Csp3–H Csp2–H) allows simultaneous generation three chemical two rings step. reaction features operational simplicity, broad substrate scope (>70 examples), good compatibility, suitability derivation some bioactive molecules. Various control kinetic isotope effect experiments were performed understand mechanism. DFT investigations support interesting imine α-carbon radical addition/1,5-hydrogen transfer/homolytic aromatic substitution cascade process.

Language: Английский

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Recent green chemistry approaches for pyrimidine derivatives as a potential anti-cancer agent: An overview (2013–2023)

Sustainable Chemistry and Pharmacy, Journal Year: 2023, Volume and Issue: 37, P. 101374 - 101374

Published: Dec. 5, 2023

Language: Английский

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Aligned Bamboo Fiber‐Induced Crystallinity Mitigation of Lightweight Polymer Composite Enables Ultrahigh Strength and Unprecedented Toughness

Advanced Functional Materials, Journal Year: 2024, Volume and Issue: 34(27)

Published: March 1, 2024

Abstract Lightweight polymer composites promise incredible applications in aerospace, seaprobes, and medical apparatus. However, their performance is generally limited by a trade‐off between mechanical strength toughness. Herein, crystallinity mitigating strategy driven highly aligned bamboo macrofibers embedded polycaprolactone polyol (PCL) matrix for producing ultrastrong tough lightweight proposed. The have oxygen‐containing functional groups on the fiber surface, that can interact with (ester hydroxyl groups) molecular chains of PCL form hydrogen bonds, thus preventing aggregation crystallization PCL, which ultimately leads to unprecedented Meanwhile, macrofibres intrinsically microstructure, enable effective stress transfer dissipation, providing remarkable ultrahigh strength. As result, obtained composite achieves (31.5 MPa) superior toughness (21.7 MJ m −3 ) at an low density (1.07 g cm ), representing state‐of‐the‐art reported polymers. Such has potential greatly expedite practical realization artificial materials, including orthopedic instruments joint prostheses.

Language: Английский

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Rhodium(III)-Catalyzed Oxidative C–H Alkylation of Aniline Derivatives with Allylic Alcohols To Produce β-Aryl Ketones

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(8), P. 4394 - 4401

Published: March 29, 2022

The Rh(III)-catalyzed C–H oxidative alkylation of aniline derivatives with readily available secondary allyl alcohols using a pyrimidine-directing group, leading to the production β-aryl ketones, is described. A wide variety functional groups are tolerated in reaction. In reaction an alcohol bearing methyl group at α-hydroxy carbon, such as but-3-en-2-ol (2a), metal oxidant not required. sharp contrast, no occurs when 2a replaced ethyl, propyl, pentyl, and phenyl groups. these cases, addition Ag2CO3 necessary for proceed successfully. Mechanistic experiments suggest that acts alkylating reagent well through β-hydroxy elimination regenerate active Rh(III) species. required species reactants other than 2a. Thus, catalyst regeneration step different depending on structure alcohol.

Language: Английский

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Imine induced metal-free C–H arylation of indoles

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(24), P. 6063 - 6069

Published: Jan. 1, 2023

A simple, mild, and metal- extra-auxiliary group-free method for the direct arylation of indole-3-carbaldehydes induced by an in situ generated transient directing group was developed.

Language: Английский

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Deciphering the Mechanistic Insights of Temporary Directing-Group-Assisted meta-Alkenylation of Complex Biaryl Systems

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(16), P. 11091 - 11103

Published: Aug. 7, 2023

The recently developed palladium-catalyzed C(sp2)–H olefination of 2-arylbenzaldehyde with the aid a temporary directing group (TDG) via reversible imine formation delivers selective meta-C–H functionalization and possesses significant advantages over well-established covalently attached (DG) approach. In this report, combined computational experimental investigation has been performed to elucidate detailed reaction mechanism origins such remote meta-selectivity. proceeds in three major steps: C–H activation, 1,2-migratory insertion, β-hydride elimination. While insertion olefin is found be turnover-determining step, selectivity predetermined by preceding activation step. observations have corroborated along experimentally conducted order determination studies, primary kinetic isotope effect (PKIE) study, free energy correlation Hammett plots. A DG-bound Pd complex shown competent promote meta-alkenylation. All possible Pd-catalyzed template-directed (ortho′, ortho, meta, para) olefinations 2-aryl benzaldehyde/aniline computationally investigated. density functional theory (DFT)-based computations indicated that other reactions necessitate higher barriers compared meta-olefination. Distortion-interaction analysis (DIA), noncovalent interaction (NCI) analysis, isodesmic studies were executed unravel mystery behind origin meta-regioselectivity.

Language: Английский

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