Recent Advances in Photo-promoted Generalized C3-H Alkylation of Quinoxalin-2(1H)-ones

Organic & Biomolecular Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

Recent advances in the photo-promoted C3–H alkylation reaction of quinoxalin-2(1 H )-ones with different agents.

Язык: Английский

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(E)‐Selective Olefination by a Cofactor‐Inspired Quinone Catalysis

ChemCatChem, Год журнала: 2025, Номер unknown

Опубликована: Май 21, 2025

Abstract In this study, we report a photothermal method that prepares ( E )‐olefins from methyl‐substituted heteroarenes under very mild reaction conditions. The photocatalyst is pyrene dione (PD) molecule has significant absorbance in the visible light spectrum and can afford persistent semiquinonate radical owing to π‐delocalized backbone. This conducts hydrogen atom transfer reactions facilitate dehydrogenation of large number alcohols. Leveraging on dehydrogenating ability PD easily 2e − /2H + redox shuttles, olefination was conducted heteroarene methyl, fluorenes Furthermore, catalytic process works aerobic conditions since oxygen regenerates catalyst. methodological development improvement over many transition metal catalysts for task, which often work at high temperature anaerobic

Язык: Английский

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A Single Terminal [Ni^II−OH] Catalyst for Direct Julia‐Type Olefination and α‐Alkylation Involving Sulfones and Alcohols

Chemistry - A European Journal, Год журнала: 2024, Номер 30(35)

Опубликована: Апрель 22, 2024

Abstract A terminal [Ni II −OH] complex 1 , supported by triflamide‐functionalized NHC ligands, showed divergent reactivity for the reaction of sulfone with alcohol, contingent on base concentration, temperature, and time. Julia‐type olefination alcohols sulfones was achieved using one equiv. base, whereas lowering loading to 0.5 afforded α ‐alkylated sulfones. Besides excellent substrate scope selectivity, biologically active stilbene derivatives DMU‐212, pinosylvin, resveratrol, piceatannol were synthesized in high yield under conditions. An extensive array controlled experiments DFT calculations provide valuable insight pathway.

Язык: Английский

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Nitrobenzene and Aniline‐Mediated Direct Olefination of Methyl Substituted N‐Heteroarenes With Benzylic Alcohols

ChemistrySelect, Год журнала: 2024, Номер 9(44)

Опубликована: Ноя. 1, 2024

Abstract Metal‐free, strong‐base‐free, and solvent‐free synthesis of alkenyl heteroarenes through PhNO 2 /PhNH mediated direct olefination methyl substituted N ‐heteroarenes with benzylic alcohols was described. Detailed mechanistic studies indicated that in situ formed imine the active intermediate for olefination. protected from overoxidation, PhNH not only acted as coupling partner formation imine, but also provides an alkaline condition generation enamine salt. Gram scale reaction three pharmaceutically relevant conjugated olefins were successful using this methodology.

Язык: Английский

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Silver‐Catalyzed Olefination of Aryl Aldehydes Using Propiolates

Chemistry - A European Journal, Год журнала: 2024, Номер 30(48)

Опубликована: Июнь 11, 2024

Olefination of aldehydes is one the fundamental reactions in organic synthesis. The commonly used Wittig olefination reaction however uses stoichiometric quantities reagents under basic conditions resulting amounts byproducts. Known catalytic alternate to requires silane reducing agents and high temperature. Herein, we report a base-free aryl using propiolates as surrogate for Witting reagent silver catalysis. Trimethyl orthoformate, presence catalyst adds alkynoate form nucleophilic allenolate which reacts with reactive oxocarbenium ion formed from aldehyde conditions. Subsequently, decarbonylation occurs olefin. Trans olefin exclusively simple cinnamaldehydes. Such conceptually novel has not been explored so far.

Язык: Английский

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Pd/S cooperativity: from stoichiometric activation of Si−H bonds to catalytic hydrosilylation

ChemistryEurope, Год журнала: 2024, Номер 3(1)

Опубликована: Ноя. 12, 2024

Abstract With the aim to explore metal‐ligand cooperation across Pd−S linkages, we designed a quinoline‐based PNS tridentate ligand and prepared Pd(II) complexes thereof. Optimal solubility stability of dicationic complex [(PNS)Pd(II)] 2 2+ IV were achieved with B(C 6 F 5 ) 4 – as counter‐anion. It adopts thiolate‐bridged dimeric structure (PdS) core, but readily activates hydrosilanes linkage. The resulting mononuclear hydride [(PNS SiR3 )Pd(II)H] + VI was characterized by multi‐nuclear NMR spectroscopy Si−H bond coordination/activation studied computationally. Complex found efficiently catalyze hydrosilylation alkynes, internal well terminal, good stereo regioselectivity.

Язык: Английский

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Recent Advances in Homogeneous Catalysts for the Acceptorless Dehydrogenation of Alcohols to Ketones and Aldehydes

Journal of Organometallic Chemistry, Год журнала: 2024, Номер 1024, С. 123445 - 123445

Опубликована: Ноя. 16, 2024

Язык: Английский

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