Stereoselective synthesis of fused-, spiro- and bridged heterocycles via cyclization of isoquinolinium salts: a recent update

Organic & Biomolecular Chemistry, Journal Year: 2022, Volume and Issue: 20(9), P. 1838 - 1868

Published: Jan. 1, 2022

Isoquinoline and its derivatives are ubiquitous in natural alkaloids, synthetic materials pharmaceuticals with a broad spectrum of biological activities. In particular, isoquinolinium salts important organic synthesis because they can serve as building blocks for the rapid construction various condensed heterocyclic systems involving cyclization processes. This review highlights novel stereoselective strategies that emerged last few years (2014-2021) fused-, spiro- bridged heterocycles exploiting bench-stable or situ generated salts. Most reactions described here provide quick access to desired products high stereoselectivity starting from readily available under mild conditions. The potential most transformations was confirmed by gram-scale production target molecules. Some have been useful other bioactive compounds.

Language: Английский

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Recent Applications of Quinolinium Salts in the Synthesis of Annulated Heterocycles

SynOpen, Journal Year: 2022, Volume and Issue: 06(02), P. 86 - 109

Published: April 25, 2022

Abstract Quinoline derivatives are frequently found in natural products and biologically active compounds; however, construction of quinoline fused polyheterocycles is a challenging goal synthetic organic chemistry. In this regard, quinolinium salts meet the demand to great level, as they can be synthesized readily employed effectively for rapid condensed heterocyclic core. The present review focuses on recent (2015–2021) applications different salts, which react with suitable partners access diverse annulated products. Most reactions discussed here involve easily available starting materials, operationally simple, offer high atom-efficiency, environmentally benign. Mechanistic aspects representative transformations have also been highlighted better understand reaction pathways. 1 Introduction 2 Annulation Involving N-Alkyl Quinolinium Salts 2.1 Reaction Alkenes 2.2 Alkynes/Arynes 2.3 Phenolic Compounds 2.4 Cyclic/Acyclic Diketones 2.5 Amines/Cyclic Amines 2.6 Enamines 2.7 Isocyanoacetates 2.8 Cyclopropanes 2.9 Ring Expansion Reactions 3 Zwitterionic Tosylates 3.1 3.2 Allenes/Ketenes 3.3 Aldehyde-Amino Acid (Azomethine Ylide) 3.4 Sulfonium 3.5 Diazoacetate 4 Thiolates 4.1 4.2 Sulfenes 4.3 Arynes 5 N-Oxides 5.1 Diynes Ynones 5.2 Lactonization Acrylate 6 N-Iminoquinolinium 6.1 Allenoates 6.2 Hydroxymethylallyl Carbonate 7 Miscellaneous Cyclizations 8 Conclusions

Language: Английский

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Metal-free photoinduced alkylative [3 + 2] annulation of terminal alkynes with N-alkyl isoquinolin-2-iums by catalytic isoquinoline-based electron donor–acceptor complex

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(5), P. 1173 - 1181

Published: Jan. 1, 2023

Catalytic isoquinoline-based EDA complex photoreduced alkylative [3 + 2] annulation of alkynes with N -alkyl isoquinolin-2-iums toward pyrrolo[2,1- a ]isoquinolines is depicted.

Language: Английский

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Copper(I)-Catalyzed Formation of Isoquinoline and Quinoline Substituted Isobenzofurans

Organic Letters, Journal Year: 2022, Volume and Issue: 24(15), P. 2899 - 2904

Published: April 11, 2022

An efficient synthetic organic transformation was developed to access isoquinoline-substituted isobenzofurans by reaction of substituted 1,5-diynes with isoquinoline N-oxides. Moderate excellent yields isoquinoline-derived were achieved formation a new C–C and two C–O bonds in the presence copper catalyst one pot. whereas quinoline-substituted obtained when conducted using quinoline N-oxides catalyst.

Language: Английский

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A Convenient Synthesis of Polysubstituted Coumarin‐pyrrolo[2,1‐a]isoquinoline‐1‐carbaldehydes from Isoquinoline, 2‐Bromoacetophenones and Coumarin‐β‐chlorovinyl Aldehydes

ChemistrySelect, Journal Year: 2021, Volume and Issue: 6(45), P. 12960 - 12964

Published: Dec. 3, 2021

Abstract In this research, a simple and efficient strategy for the straightforward synthesis of polysubstituted coumarin‐pyrrolo[2,1‐ ]isoquinoline‐1‐carbaldehydes is presented by sequential three‐component reaction isoquinoline, 2‐bromoacetophenones 3‐chloro‐3‐(2‐oxo‐2 H ‐chromen‐3‐yl)acrylaldehydes as readily available starting materials, which includes base‐mediated 1,4‐addition or [3+2] cycloaddition/intramolecular cyclization/formation two C−C bonds/aromatization tandem under air. method, chemoselective cascade process, easily accessible energy conserving (short times at room temperature), simplicity product purification (the products can be purified washing with EtOH), excellent yields (75–88 %), metal‐free catalyst, green mild conditions in one‐pot are important highlighted advantages protocol.

Language: Английский

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Phosphine-Catalyzed Synthesis of 3-Allyl-4-pyrones by the Tandem Reaction of Diynones and Allylic Alcohols

The Journal of Organic Chemistry, Journal Year: 2021, Volume and Issue: 86(21), P. 14476 - 14484

Published: Oct. 18, 2021

A simple and effective tandem reaction of diynones allylic alcohols was developed to afford functionalized 3-allyl-4-pyrones in moderate excellent yields. This protocol underwent a Michael addition─Claisen rearrangement─O-cyclization process, which exhibited broad substrate tolerance, high regioselectivity, atom economy under metal-free condition. Moreover, functional transformation the products also further studied.

Language: Английский

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Base-Promoted Decarboxylative Annulation of Methyl 2-(2-Bromophenyl)acetates and Ynones to Access Benzoxepines

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 88(5), P. 3079 - 3088

Published: Feb. 17, 2023

A simple and efficient base-mediated decarboxylative annulation of ynones with methyl 2-(2-bromophenyl)acetates has been developed. broad range benzoxepines were prepared a substrate scope high regioselectivity in moderate to excellent yields under transition-metal-free conditions. This method proceeds through tandem [2 + 4] annulation, ring-opening reaction, the intramolecular nucleophilic aromatic substitution reaction. Additionally, key intermediates successfully obtained characterized unambiguously by single-crystal X-ray crystallography, which could favorably support mechanism. Furthermore, gram-scale reaction synthetic applications for further functionalization are also studied.

Language: Английский

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Synthetic Approaches for Annulated Quinolines at Face a

Polycyclic aromatic compounds, Journal Year: 2023, Volume and Issue: 44(4), P. 2863 - 2886

Published: June 21, 2023

The essential focus of the present review is to collect synthetic methods for quinolines fused heterocycles at face a. A diversity a was efficiently synthesized by several under different reaction conditions. current covers reactions developed synthesis annulated

Language: Английский

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Ag(I)-Mediated Annulation of 2-(2-Enynyl)pyridines and Propargyl Amines to Access 1-(2H-Pyrrol-3-yl)indolizines

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 89(1), P. 304 - 312

Published: Dec. 21, 2023

An effective Ag(I)-mediated annulation of 2-(2-enynyl)pyridines and propargyl amines was developed, unexpectedly affording a broad range functionalized 1-(2H-pyrrol-3-yl)indolizines in moderate to excellent yields. The developed method is characterized by operational simplicity, ready availability starting materials, high regioselectivity, substrate scope under mild reaction conditions. Ag(I)-promoted cyclization possibly results the formation spiroindolizine, ring-opening rearrangement which may give 1-(2H-pyrrol-3-yl)indolizine. Furthermore, gram-scale synthetic transformations are also studied.

Language: Английский

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Recent advances in the synthesis of pyrrolo[1,2-a]quinolines

Chemistry of Heterocyclic Compounds, Journal Year: 2023, Volume and Issue: 59(11-12), P. 723 - 729

Published: Dec. 1, 2023

Language: Английский

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