A solvent and transition metal-free, highly efficient Brønsted acidic ionic liquid promoted one-potthree-component reactions for the synthesis of tetrasubstituted pyrroles

Atar, Amol B.; Han, Eunbi; Sohn, Dae Hyup; Kang, Jongmin

doi:10.1080/00397911.2019.1593460

Cited by 12 publications

(4 citation statements)

References 25 publications

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“…The resonance band assigning to the H atom of ‐SO 3 H in [SO 3 H‐BMIm][OTf] mixing with 1 shifted to 8.46 ppm from initial 8.39 ppm (Figure a), meanwhile the band to the O atoms of 1 shifted from 18.11 to 18.19 ppm with the signal to the O atoms of [OTf] − keeping unchanged (Figure b). Combining with the fact that SO 3 H‐functionalized cation is necessary for catalyzing the reaction, it can be deduced that the O atom in ether forms H‐bond with the H atom from ‐SO 3 H in cation . The 19 F NMR spectra of the IL mixing with 1 showed two new peaks accompanied with obvious downfield shift of the original peak (Figure c), meanwhile the highfield shifts of the H atoms of 1 were observed in 1 H NMR spectra of the mixture (Figure a).…”

Section: Methodsmentioning

confidence: 92%

Hydrogen‐Bonding Catalyzed Ring‐Closing C−O/C−O Metathesis of Aliphatic Ethers over Ionic Liquid under Metal‐Free Conditions

et al. 2020

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O‐heterocycles have wide applications, and their efficient and green synthesis is very interesting. Herein, we report hydrogen‐bonding catalyzed ring‐closing metathesis of aliphatic ethers to O‐heterocycles over ionic liquid (IL) catalyst under metal‐ and solvent‐free conditions. The IL 1‐butylsulfonate‐3‐methylimidazolium trifluoromethanesulfonate ([SO3H‐BMIm][OTf]) is discovered to show outstanding performance, better than the reported catalysts. An interface effect plays an important role in mediating the reaction rate due to the immiscibility between the products and the IL catalyst, and the products can be spontaneously separated. NMR analysis and DFT calculation suggest that a pair of cation and anion of [SO3H‐BMIm][OTf] could form three strong H‐bonds with an ether molecule, which catalyze the ether transformation via a cyclic oxonium intermediate. A series of O‐heterocycles including tetrahydrofurans, tetrahydropyrans, morpholines and dioxane can be obtained from their corresponding ethers in excellent yields (e.g., >99 %). This work opens an efficient and metal‐free way to produce O‐heterocycles from aliphatic ethers.

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Section: Methodsmentioning

confidence: 92%

Hydrogen‐Bonding Catalyzed Ring‐Closing C−O/C−O Metathesis of Aliphatic Ethers over Ionic Liquid under Metal‐Free Conditions

et al. 2020

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“…Atar and co‐workers demonstrated the use of three‐component reactions for the synthesis of tetrasubstituted pyrroles 9 through a one‐pot annulation of β‐nitrostyrene 8 , amines 3 , and dialkyl acetylene dicarboxylates 2 , employing imidazolium Brønsted acidic ionic liquid (BAIL) as a catalyst and solvent (Scheme 2). [18] Initially, the reaction proceeds via formation of an enaminone 12 by the reaction between amine 3 and dialkylacetylene dicarboxylate 2 . Next, β‐nitrostyrene 8 undergo the nucleophilic addition with enaminone 12 to formed intermediate 13 which undergo subsequent cyclization to form adduct 14 .…”

Section: Five‐membered Heterocyclic Compoundsmentioning

confidence: 99%

Transition‐Metal‐Free Synthesis of N‐Heterocyclic Compounds via Multi‐Component Reactions

et al. 2023

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Multicomponent reactions (MCRs) have emerged as powerful tools in synthetic chemistry for the efficient synthesis of diverse molecular scaffolds, particularly nitrogen‐containing heterocycles. Despite their numerous advantages, the use of transition metal catalysts or additives in MCRs can present limitations due to cost, toxicity, and environmental concerns. In recent years, there has been a growing interest in transition metal‐free MCRs for the synthesis of N‐heterocyclic compounds. This review provides a comprehensive and concise overview of the recent advancements in transition metal‐free MCRs for the synthesis of valuable N‐heterocycles over the past five years. The review is systematically organized, categorizing the discussed MCRs based on the size of the heterocyclic ring and the number of nitrogen atoms. Only MCRs that result in the formation of heterocyclic rings containing at least one nitrogen atom are included, while the derivatization of N‐heterocycles using transition metal‐free MCRs falls outside the scope of this review. By highlighting the recent developments in this field, this review aims to showcase the potential and significance of transition metal‐free MCRs as sustainable and efficient strategies for accessing N‐heterocyclic compounds. The elimination of transition metals not only simplifies the reaction conditions but also contributes to greener and more environmentally friendly synthetic approaches. This review serves as a valuable resource for researchers interested in the design and application of transition metal‐free MCRs in the synthesis of nitrogen‐containing heterocycles.

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“…for the synthesis of tetra ‐substituted pyrrols 27 by utilizing DBAL‐2 via the one‐pot reaction of dialkyl acetylenedicarboxylate 1 , amines 2 and β ‐nitrostyrene 25 at room temperature under solvent‐free condition (Scheme 11). [20] …”

Section: Synthesis Of Five‐membered Rings With One Heteroatom Includingmentioning

confidence: 99%

“…[19] A green and significant approach was developed in 2019 by Balu Atar et al for the synthesis of tetra-substituted pyrrols 27 by utilizing DBAL-2 via the one-pot reaction of dialkyl acetylenedicarboxylate 1, amines 2 and β-nitrostyrene 25 at room temperature under solvent-free condition (Scheme 11). [20] A green and effective method was developed in 2021 by Nazeri et al for the synthesis of substituted pyrroles 29 from the reaction of 5-amino-pyrazoles 28, aldehydes 6, dialkyl acetylenedicarboxylate 1 and isocyanides 12 in the presence of PTSA . H 2 O in CH 3 CN under ultrasound irradiation (Scheme 12).…”

Section: Pyrrolesmentioning

confidence: 99%

Use of Dialkyl Acetylenedicarboxylates in the Multicomponent Synthesis of Heterocyclic Structures

2022

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Dialkyl acetylenedicarboxylates (DAAD) are the class of acetylenic compounds that are broadly used in organic synthesis in a noticeable quantity. Their wide application has made them an important moiety in heterocyclic compounds and drug discovery programs. Dialkyl acetylenedicarboxylate is a di-ester in which the ester groups are conjugated with a carbon-carbon triple bond. As such, the molecule is very electrophilic, and is broadly used as a dienophile in various cycloaddition reactions, for example the Diels-Alder reaction. In addition, it is a strong Michael acceptor. Due the importance of dialkyl acetylenedicarboxylate in organic synthesis, we are trying to show the applications of this compound in the synthesis of different heterocycles using multicomponent reactions. In this review, we show recent advances (2016)(2017)(2018)(2019)(2020)(2021)(2022) for the synthesis of various heterocycles that have different ring sizes (five, six and seven membered, Spiro and fused heterocycles), using DAAD via multicomponent reactions.

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A solvent and transition metal-free, highly efficient Brønsted acidic ionic liquid promoted one-potthree-component reactions for the synthesis of tetrasubstituted pyrroles

Cited by 12 publications

References 25 publications

Hydrogen‐Bonding Catalyzed Ring‐Closing C−O/C−O Metathesis of Aliphatic Ethers over Ionic Liquid under Metal‐Free Conditions

Hydrogen‐Bonding Catalyzed Ring‐Closing C−O/C−O Metathesis of Aliphatic Ethers over Ionic Liquid under Metal‐Free Conditions

Transition‐Metal‐Free Synthesis of N‐Heterocyclic Compounds via Multi‐Component Reactions

Use of Dialkyl Acetylenedicarboxylates in the Multicomponent Synthesis of Heterocyclic Structures

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