Reductive Functionalization of Pyridine-Fused N-Heteroarenes

Accounts of Chemical Research, Journal Year: 2024, Volume and Issue: 57(5), P. 795 - 813

Published: Feb. 23, 2024

ConspectusThe selective functionalization/transformation of ubiquitous pyridine-fused N-heteroarenes is a practical method to synthesize structurally novel N-heterocycles, which important for the development medicines, bioactive agents, agrochemicals, materials, ligands, sensors, pigments, dyes, etc. However, owing thermodynamic stability, kinetic inertness, and lone electron pair–induced catalyst deactivation N-heteroarenes, limited strategies (e.g., C–H activation/functionalization, electrophilic substitution, Minisci reaction) are available realize synthetic purpose maintain aromaticity final products. Moreover, relevant transformations have limitations such as needing harsh reaction conditions, requiring preinstallation specific coupling agents containing transformable functionalities or directing groups, using less environmentally benign oxidants and/or acidic activators, poor selectivity. Herein, considering that imines, enamines, radicals, cyclic amines generated during reduction precise transformation these reductive intermediates offers fundamental basis developing tandem reactions. Our group revealed slow rate, synergistic catalysis, controlled electroreduction effective fulfilling functionalization N-heteroarenes. Thus, we established series new methods provide diverse construction modalities functionalized N-heterocycles. The striking features include high efficiency, atom economy, use readily accessible feedstocks in absence flammable pressurized H2 gas, alongside promising potential obtained N-heterocyclic present study would be appealing fields organic chemistry, biomedical functional materials. This Account describes application dearomatization substrate-activating reaction-initiating modes summarizes via alkylation, arylation, annulation at nitrogen, α, β, other remote carbon sites achieved over past 8 years. Details regarding reactions their plausible mechanisms perspectives discussed. We hope our contributions this field will aid further tackle intractable challenges area.

Language: Английский

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Ruthenium-Catalyzed Straightforward Synthesis of 1,2,3,4-Tetrahydronaphthyridines via Selective Transfer Hydrogenation of Pyridyl Ring with Alcohols

Organic Letters, Journal Year: 2015, Volume and Issue: 17(16), P. 4054 - 4057

Published: Aug. 7, 2015

Through a ruthenium-catalyzed selective hydrogen transfer coupling reaction, novel straightforward synthesis of 1,2,3,4-tetrahydronaphthyridines from o-aminopyridyl methanols and alcohols has been developed. The synthetic protocol proceeds in an atom- step-economic fashion together with the advantages operational simplicity, broad substrate scope, production water as only byproduct, no need for external reducing reagents such high pressure H2 gas, offering highly practical approach accessing this type structurally unique products.

Language: Английский

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Calix[n]arene-Catalyzed Three-Component Povarov Reaction: Microwave-Assisted Synthesis of Julolidines and Mechanistic Insights

The Journal of Organic Chemistry, Journal Year: 2018, Volume and Issue: 83(4), P. 1761 - 1771

Published: Jan. 16, 2018

A new one-pot cascade reaction-based application of Povarov reactions with a p-sulfonic acid calix[4]arene catalyst for the synthesis series 34 julolidine derivatives substituents at C8 or C9 in good to excellent yields is reported. These microwave-assisted proceeded efficiently, had short reaction times, were metal-free, low cost, and used an inexpensive, easily available nontoxic catalyst. advantages, along simple workup procedure, make this protocol very efficient green alternative traditional methods constructing these types N-heterocyclic skeletons. In addition, allows formation structures, which requires construction four C-C bonds two C-N bonds. mechanism involving stepwise sequence via ionic intermediates was proposed validated.

Language: Английский

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Vicinal α,β‐Functionalizations of Amines: Cyclization Versus Dehydrogenative Hydrolysis

Chemistry - A European Journal, Journal Year: 2015, Volume and Issue: 21(41), P. 14319 - 14323

Published: Aug. 18, 2015

Abstract Direct vicinal α,β‐difunctionalization of tertiary cyclic amines is achieved in the presence ruthenium or iridium transition‐metal complexes featuring phosphine‐sulfonate chelates. By varying reaction conditions, α‐alkylated lactams were obtained by a formal dehydrogenative hydrolysis which one molecule hydrogen generated from water.

Language: Английский

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Reductive electrophilic C–H alkylation of quinolines by a reusable iridium nanocatalyst

Chemical Science, Journal Year: 2021, Volume and Issue: 12(41), P. 13802 - 13808

Published: Jan. 1, 2021

The incorporation of a coupling step into the reduction unsaturated systems offers desirable way for diverse synthesis functional molecules, but it remains to date challenge due difficulty in controlling chemoselectivity. Herein, by developing new heterogeneous iridium catalyst composed Ir-species (Ir δ+) and N-doped SiO2/TiO2 support (Ir/N-SiO2/TiO2), we describe its application reductive electrophilic mono dialkylations quinolines with various 2- or 4-functionalized aryl carbonyls benzyl alcohols utilizing renewable formic acid as reductant. This catalytic transformation practical platform direct access vast range alkyl THQs, proceeding excellent atom-efficiency, good substrate scope group tolerance, reusable abundantly available feedstocks, generation water carbon dioxide by-products. work opens door further develop more useful organic transformations under catalysis.

Language: Английский

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Direct Construction of Julolidines via Reductive Annulation of Quinolines and Conjugated Enones by a MOF-Derived Hierarchically Porous Iridium Catalyst

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(16), P. 10294 - 10303

Published: Aug. 5, 2022

Here, we describe the development of a MOF-derived hierarchically porous ZrO2-supported iridium catalyst (Ir-N@HP-mesoZrO2), featuring sufficient accessible catalytic sites even with ultralow loading. Such was successfully applied to selective and direct construction julolidines via reductive annulation readily available quinolines conjugated enones, proceeding good substrate functional group compatibility, reusable catalyst, high step atom efficiency, easy applicability for fabrication molecules. The present work opens door further develop useful transformations by merging hydrogen transfer-mediated activation in situ incorporation coupling sequence under heterogeneous catalysis.

Language: Английский

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An Efficient Homogenized Ruthenium(II) Pincer Complex for N -Monoalkylation of Amines with Alcohols

European Journal of Organic Chemistry, Journal Year: 2017, Volume and Issue: 2017(24), P. 3481 - 3486

Published: June 28, 2017

An ionic 2,6-bis(imidazo[1,2-α]pyridin-2-yl)pyridine-based N^N^N pincer ruthenium(II) complex exhibited high efficiency in the C–N bond formation between amines and alcohols by “borrowing hydrogen” (BH) or “hydrogen autotransfer” (HA) concept. The synthetic protocol selectively generated monoalkylated without of tertiary during reaction. unique selectivity enabled symmetrically asymmetrically substituted diamines. This methodology features several advantages including a low catalyst loading (as as 0.5 mol-%), short reaction time 2 h), excellent N-monoalkylation selectivity.

Language: Английский

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Fluorescent half-sandwich phosphine-sulfonate iridium(III) and ruthenium(II) complexes as potential lysosome-targeted anticancer agents

Dyes and Pigments, Journal Year: 2018, Volume and Issue: 162, P. 821 - 830

Published: Nov. 8, 2018

Language: Английский

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Synthesis and Derivatization of Julolidine: A Powerful Heterocyclic Structure

European Journal of Organic Chemistry, Journal Year: 2019, Volume and Issue: 2019(27), P. 4273 - 4310

Published: June 26, 2019

Julolidines constitute a class of N ‐heterocycle compounds which have in common the 2,3,6,7‐tetrahydro‐1 H ,5 ‐benzo[1,2]quinolizine ring. Due mainly to its fluorescence properties, such structures shown potential application range scientific and technological areas attracted attention great variety research groups. For example, julolidines been used for detection ions volatile environmental biological samples, construction dye‐sensitized solar cells, photoconductive materials as fluorescent sensors bioimaging. This review summarizes strategies reported synthesis julolidine ring principal modifications obtaining more complex derivatives with improved properties these compounds. In this context, aldol condensation, olefination, imine synthesis, cross‐coupling reactions extensively explored discussed. Examples applications, illustrate structures, will also be briefly presented.

Language: Английский

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From byproducts to NLO-active dyes: catalyst-free transfer hydrogenation in the modular synthesis of merocyanines

New Journal of Chemistry, Journal Year: 2024, Volume and Issue: 48(19), P. 8578 - 8588

Published: Jan. 1, 2024

Direct transfer hydrogenation from a strong electron donor to highly polarizable hemicyanines was discovered in the synthesis of push–pull chromophores. The reaction mechanism and experimental results were elucidated using DFT calculations.

Language: Английский

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