Synthesis of pyrrolo[1,2-<i>a</i>]quinolines by formal 1,3-dipolar cycloaddition reactions of quinolinium salts

Choi, Anthony; Morley, Rebecca M; Coldham, Iain

doi:10.3762/bjoc.15.149

Cited by 16 publications

(10 citation statements)

References 56 publications

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“…Indeed, in a catalyst-free 32CA process, the relative substituents configuration within addents moieties, stereospecificity is lost, when the mechanism turns from a one-step route to a stepwise one. Subsequently, parallel reaction channels leading to the emergence of stereoisomers and some other impurities will be opened [18][19][20]. Obviously, such problems in the stepwise routes are the result of emergence the diradical or zwitterionic acyclic intermediates.…”

Section: Introductionmentioning

confidence: 99%

The extraordinary gravity of three atom 4π-components and 1,3-dienes to C20-nXn fullerenes; a new gate to the future of Nano technology

Siadati

Rezazadeh

2022

Sci. Rad

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A quick glance to the adsorption, sensing, and energy storage abilities of C20 fullerene and its derivatives indicate that this small carbon cluster may have extraordinary properties which would make it a key part of the future of Nano actuators and Nano machines. For example, in the case of the gravity of three atom 4π-components (TACs) to these carbon cages, it should be noted that; the rate constants (K)s of the reaction of C20 fullerene with 1,3-butadiene (Diels-Alder (DA) process), and with 2-furan nitrile oxide ([3+2] cycloaddition (32CA process)) are 2.51(1011) M-1 s-1, and 1.4(107)M-1 s-1, respectively. However, the rate constant of the 32CAreaction between norbornadiene and 3,4-dihydro isoquinoline-N-oxide is about 2.56(10-5) M-1 s-1 (both by DFT and by experimental results). This simple comparison could show the extraordinary gravity of some TACs and dienes to C20 fullerenes.

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Section: Introductionmentioning

confidence: 99%

The extraordinary gravity of three atom 4π-components and 1,3-dienes to C20-nXn fullerenes; a new gate to the future of Nano technology

Siadati

Rezazadeh

2022

Sci. Rad

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“…It involved the reaction of quinolinium bromides 5 bearing an ester or amide group with arylidene malononitriles 79 in the presence of trimethylamine ( Scheme 58 ). 94 After deprotonation of the quinolinium salts, the in situ generated quinolinium ylides underwent (3 + 2) dipolar cycloaddition with the electron-poor alkenes to afford pyrrolo[1,2- a ]quinolines 80 as single regio- and diasteroisomers in good yields ( Scheme 58 , eq 1). The reaction was further extended to N -methyl maleimide as dipolarophile, rendering tetracyclic pyrroloquinolines 81 , again as single diastereoisomers in very good yields ( Scheme 58 , eq 2).…”

Section: Cycloaddition Reactions and Annulationsmentioning

confidence: 99%

Recent Strategies in the Nucleophilic Dearomatization of Pyridines, Quinolines, and Isoquinolines

Escolano,

Gaviña,

Alzuet-Piña

et al. 2024

Chem. Rev.

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Dearomatization reactions have become fundamental chemical transformations in organic synthesis since they allow for the generation of three-dimensional complexity from two-dimensional precursors, bridging arene feedstocks with alicyclic structures. When those processes are applied to pyridines, quinolines, and isoquinolines, partially or fully saturated nitrogen heterocycles are formed, which are among the most significant structural components of pharmaceuticals and natural products. The inherent challenge of those transformations lies in the low reactivity of heteroaromatic substrates, which makes the dearomatization process thermodynamically unfavorable. Usually, connecting the dearomatization event to the irreversible formation of a strong C−C, C− H, or C−heteroatom bond compensates the energy required to disrupt the aromaticity. This aromaticity breakup normally results in a 1,2-or 1,4-functionalization of the heterocycle. Moreover, the combination of these dearomatization processes with subsequent transformations in tandem or stepwise protocols allows for multiple heterocycle functionalizations, giving access to complex molecular skeletons. The aim of this review, which covers the period from 2016 to 2022, is to update the state of the art of nucleophilic dearomatizations of pyridines, quinolines, and isoquinolines, showing the extraordinary ability of the dearomative methodology in organic synthesis and indicating their limitations and future trends.

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“…In 2019, Coldham and co-workers carried out the reaction of quinolinium salts 1 with electron-deficient alkenes (arylidene malononitriles) 2 in the presence of triethylamine to afford pyrrolo[1,2- a ]quinoline derivatives 3 (Scheme 1 ). 37 The reaction proceeded via formal [3+2] cycloaddition with high regio- and stereoselectivity, producing a single stereoisomer in good yields under mild reaction conditions. The scope of the reaction was further expanded by using N -methylmaleimide 4 as an effective dipolarophile to obtain the corresponding tetracyclic scaffolds 5 .…”

Section: Annulation Involving N -Alkyl Quinolinium Saltsmentioning

confidence: 99%

Recent Applications of Quinolinium Salts in the Synthesis of Annulated Heterocycles

Das¹

2022

SynOpen

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Quinoline derivatives are frequently found in natural products and biologically active compounds, however, construction of quinoline fused polyheterocycles is the challenging goal in synthetic organic chemistry. In this regard, quinolinium salts meet the demand to a great level, as they can be synthesized readily and employed effectively for the rapid construction of condensed heterocyclic core. The present review focuses on recent (2015-2021) applications of different quinolinium salts that react with suitable partners to access diverse annulated products. Most of the reactions discussed here involve easily available starting materials, operationally simple, high atom efficiency and environmentally benign. Mechanistic aspects of representative transformations have also been highlighted for better understanding of reaction pathway.

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Synthesis of pyrrolo[1,2-a]quinolines by formal 1,3-dipolar cycloaddition reactions of quinolinium salts

Cited by 16 publications

References 56 publications

The extraordinary gravity of three atom 4π-components and 1,3-dienes to C20-nXn fullerenes; a new gate to the future of Nano technology

The extraordinary gravity of three atom 4π-components and 1,3-dienes to C20-nXn fullerenes; a new gate to the future of Nano technology

Recent Strategies in the Nucleophilic Dearomatization of Pyridines, Quinolines, and Isoquinolines

Recent Applications of Quinolinium Salts in the Synthesis of Annulated Heterocycles

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