Recent advances on non-precious metal-catalyzed C–H functionalization of N-heteroarenes

Chemical Communications, Journal Year: 2021, Volume and Issue: 58(1), P. 10 - 28

Published: Nov. 18, 2021

N-Heteroarenes are widely used for numerous medicinal applications, lifesaving drugs and show utmost importance as intermediates in chemical synthesis. This feature article highlights the recent advances, from 2015 to August 2021, on sp2 sp3 C-H bond functionalization reactions of various N-heteroarenes catalyzed by non-precious transition metals (Mn, Co, Fe, Ni, etc.). The salient features report are: (i) development newer catalysis Csp2-H activation categorized into alkylation, alkenylation, borylation, cyanation, annulation reactions, (ii) advances Csp3-H considering approaches alkylation well alkenylation processes, (iii) synthetic applications practical utility catalytic protocols utilized late-stage drug development; (iv) scope along with mechanistic studies detail findings important processes.

Language: Английский

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Palladium complexes containing NNN pincer type ligands and their activities in Suzuki-Miyaura cross coupling reaction

Heliyon, Journal Year: 2023, Volume and Issue: 9(7), P. e17608 - e17608

Published: June 27, 2023

Five new NNN pincer-type ligands and their palladium complexes were successfully synthesised characterised by FT-IR, 1H NMR, 13C UV–vis analyses. TEM analysis was used to observe the morphological character of black residues obtained from fourth cycle reusability test. Furthermore, suitable crystals N2,N6-bis(2-tert-butylphenyl)pyridine-2,6-dicarboxamide its complex elucidated with X-ray single crystal diffraction method. Both ligand crystallise in a monoclinic system space group P21/c for H2L4 C2/c complex. The structure pincer stabilised intramolecular intermolecular C–H⋅⋅⋅O, C–H⋅⋅⋅N, N–H⋅⋅⋅N contacts. A Suzuki-Miyaura cross-coupling reaction between aryl halides phenylboronic acid assess catalytic abilities complexes. All prepared exhibited considerable activity. However, 4 (Acetonitrile-N2,N6-bis(2-tert-butylphenyl)pyridine-2,6-dicarboxamidopalladium(II)) 5 (Acetonitrile-N2,N6-bis(2-nitrophenyl)pyridine-2,6-dicarboxamidopalladium(II)) provided almost 100% conversion nearly yield 4-bromotoluene acid. these active catalysed sterically hindered deactivated substrates (1-Bromo-4-izobutylbenzene 2-bromo-6-methoxynaphthalene) acid, complete yields up achieved short time 2-bromo-6-methoxynaphthalene.

Language: Английский

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Nickel‐Catalyzed Sequential Synthesis of Alkylated Quinolines and Their Photophysical Studies

Asian Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: June 20, 2024

Abstract An efficient nickel‐catalyzed sequential one‐pot strategy for the synthesis of coumarin‐appended quinolines and bis‐quinolines has been developed under mild reaction conditions in moderate to good yields (up 84 %) via dehydrogenative Friedlander annulation followed by C(sp 3 )−H functionalization. The use a cost‐effective Ni catalyst, environmentally friendly solvents simple operating procedures are attractive attributes this method. Additionally, photophysical properties synthesized derivatives were explored utilizing UV‐vis absorption fluorescence emission studies. Furthermore, large‐scale synthetic utility highlight potential applicability organic chemistry. Moreover, A plausible mechanism is supported control experiments monitoring 1 H NMR analysis.

Language: Английский

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Transition metal-catalyzed olefination of alkyl heteroarenes with alcohols

Tetrahedron, Journal Year: 2024, Volume and Issue: 168, P. 134306 - 134306

Published: Oct. 18, 2024

Language: Английский

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NaCl as Catalyst and Water as Solvent: Highly E-Selective Olefination of Methyl Substituted N-Heteroarenes with Benzyl Amines and Alcohols

Organic Letters, Journal Year: 2020, Volume and Issue: 22(14), P. 5496 - 5501

Published: June 30, 2020

Oxidative coupling of benzylamines and alcohols with methyl substituted N-heteroarenes such as quinolines quinoxalines has been achieved using chloride, a sea abundant anion the catalyst for practical synthesis wide range E-disubstituted olefins in aqueous medium. Detailed mechanistic studies control experiments were carried out to deduce reaction mechanism which indicated that situ formed ClO2- is active form catalyst. We have successfully 1 g scale this methodology, five pharmaceutically relevant conjugated also synthesized by method moderate good yields.

Language: Английский

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Iron-catalysed alkylation of 2-methyl and 4-methyl azaarenes with alcohols via C–H bond activation

Chemical Communications, Journal Year: 2020, Volume and Issue: 56(35), P. 4777 - 4780

Published: Jan. 1, 2020

The first Fe-catalysed alkylation of 2-methyl and 4-methyl-azaarenes with a series alkyl hetero-aryl alcohols is reported (>39 examples up to 95% yield). Multi-functionalisation pyrazines synthesis anti-malarial drug (±) Angustureine significantly broaden the scope this methodology. Preliminary mechanistic investigation, deuterium labeling kinetic experiments including trapping enamine intermediate 1a' are special importance.

Language: Английский

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Atom‐Economic Alk(en)ylations of Esters, Amides, and Methyl Heteroarenes Utilizing Alcohols Following Dehydrogenative Strategies

Asian Journal of Organic Chemistry, Journal Year: 2021, Volume and Issue: 10(3), P. 464 - 484

Published: Jan. 19, 2021

Abstract Owing to the atom‐economic and greener nature, borrowing hydrogen (BH) acceptorless dehydrogenative coupling (ADC) processes have drawn significant attentions of researchers across globe thus, these strategies been extensively utilized in synthetic chemistry access various challenging valuable compounds. During last decade, progress has witnessed utilization protocols involving alkylation amides/esters/N‐heteroarenes by replacing traditionally mutagenic reagents as alkyl source with sustainable biomass derived alcohols under BH/ADC process. This includes mainly transition metal based catalytic systems although a few metal‐free are reported. In this minireview, advancement from 2010 until September 2020 accessing C‐alk(en)ylated compounds unactivated utilizing via strategy is highlighted. Additionally, reports on aldehydes instead partners also discussed.

Language: Английский

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Hf(OTf)₄-Catalyzed 1,6-Conjugate Addition of 2-Alkyl-azaarenes to para-Quinone Methides

The Journal of Organic Chemistry, Journal Year: 2021, Volume and Issue: 86(4), P. 3615 - 3624

Published: Feb. 1, 2021

Herein we reported a Hf(OTf)4-catalyzed carbon–carbon bond formation reaction between 2-alkyl-azaarenes and para-quinone methides (p-QMs). This 1,6-conjugate addition protocol offered rapid access to large array of triarylethane products in good yields. The catalyst loading could be reduced 1 mol %. Studies pertinent scale-up product derivatization were also presented.

Language: Английский

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Sequential Synthesis of Alkenylated Quinazolines Through sp³ C−H Functionalization and Their Photophysical Properties

ChemistrySelect, Journal Year: 2024, Volume and Issue: 9(33)

Published: Aug. 28, 2024

Abstract Quinazolines are biologically potent heterocyclic compounds; however, their synthesis poses high challenges. In this present study, we have developed an inexpensive cobalt metal‐catalyzed acceptorless dehydrogenative pathway for the sequential of alkenylated quinazolines from benzhydrol via dehydrogenation, cyclization, and subsequent sp 3 C−H functionalization. This transformation holds potential owing to its commercially available key starting materials, good functional tolerance, moderate reaction conditions, environmental friendliness, applicability gram‐scale synthesis. Furthermore, synthetic utility synthesized derivatives has been explored through various reactions, including reduction, halogenation, methoxylation, Michael addition, spiro cyclization. Additionally, photophysical properties indicate that nitrogen atom readily undergoes a reversible protonation, leading significant changes in colour. characteristic presents opportunity creation pH sensors with colourimetric capabilities.

Language: Английский

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Alcohols as Fluoroalkyl Synthons: Ni‐catalyzed Dehydrogenative Approach to Access Polyfluoroalkyl Bis‐indoles

Chemistry - A European Journal, Journal Year: 2020, Volume and Issue: 26(70), P. 16649 - 16654

Published: Sept. 25, 2020

Abstract An acceptorless dehydrogenative strategy for the synthesis of polyfluoroalkylated bis‐indoles is described by employing an earth‐abundant nickel‐based catalytic system under air. The notable feature present transformation use bench stable and easily affordable polyfluorinated alcohols without any pre‐functionalization introduction precious polyfluoroalkyl groups. developed straightforward protocol accomplished biologically relevant fluoroalkyl in a sustainable fashion. Extensive DFT study predicts unique role indole molecules which stabilizes transition states during dehydrogenation process alcohols, presumably through non‐covalent π⋅⋅⋅π H‐bonding interactions.

Language: Английский

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