Recent advances in the applications of pyrazolone derivatives in enantioselective synthesis

Organic & Biomolecular Chemistry, Journal Year: 2022, Volume and Issue: 20(12), P. 2370 - 2386

Published: Jan. 1, 2022

Pyrazolones and pyrazoles, featuring nitrogen-nitrogen bonds, are two of the most important classes heterocycles, owing to their widespread occurrence in medicinal chemistry functional materials. The last decade has witnessed a rapid increase construction chiral pyrazolone pyrazole derivatives, with application derivatives as powerful synthons. Since our review 2018, large number new achievements emerged this area, requiring timely update. Thus, summarizes these elegant based on multiple reactive sites different In addition, mechanisms interesting biological investigations relating corresponding products also discussed.

Language: Английский

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Recent Advances in Squaramide‐Catalyzed Asymmetric Mannich Reactions

Advanced Synthesis & Catalysis, Journal Year: 2020, Volume and Issue: 362(21), P. 4487 - 4512

Published: Sept. 19, 2020

Abstract Bifunctional squaramides as a branch of organo‐catalysts showed powerful strategies in the art asymmetric synthesis, and they have been proved to be highly efficient versatile catalysts for constructing complex molecular structures chiral biologically active compounds. In this review, we summarized recent advances bifunctional squaramide‐catalyzed Mannich reactions. magnified image

Language: Английский

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Asymmetric Synthesis of Spiropyrazolones via Chiral Pd(0)/Ligand Complex-Catalyzed Formal [4+2] Cycloaddition of Vinyl Benzoxazinanones with Alkylidene Pyrazolones

The Journal of Organic Chemistry, Journal Year: 2020, Volume and Issue: 86(2), P. 1712 - 1720

Published: Dec. 30, 2020

In the presence of chiral Pd(0)/ligand complex, vinyl benzoxazinanones underwent [4+2] cycloaddition with alkylidene pyrazolones smoothly and delivered spiropyrazolones in reasonable yields, diastereoselectivities, eneantioselectivities (up to >99% yield, >99:1 dr 99% ee). The absolute configuration obtained was unambiguously characterized use X-ray single-crystal structure analysis. Moreover, reaction mechanism assumed interpret formation target compounds.

Language: Английский

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Recent Advances in Catalytic Enantioselective Synthesis of Pyrazolones with a Tetrasubstituted Stereogenic Center at the 4-Position

Synthesis, Journal Year: 2020, Volume and Issue: 53(02), P. 215 - 237

Published: Oct. 8, 2020

Abstract Pyrazolone [2,4-dihydro-3H-pyrazol-4-one] represents one of the most important five-membered nitrogen heterocycles which is present in numerous pharmaceutical drugs and molecules with biological activity. Recently, many catalytic methodologies for asymmetric synthesis chiral pyrazolones have been established great success, specially, bearing a tetrasubstituted stereocenter at C-4. This review summarizes these excellent research studies since 2018, including representative examples some mechanistic pathways explaining observed stereochemistry. 1 Introduction 2 Catalytic Enantioselective Synthesis Chiral Pyrazolones Full Carbon Tetrasubstituted Stereocenter C-4 3 Quaternary Heteroatom 4 Spiropyrazolones 5 Conclusion

Language: Английский

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Highly Diastereodivergent Green Synthesis of Cyclohexanones via Double Michael Addition of Malononitrile to Dibenzalacetone

Tetrahedron, Journal Year: 2025, Volume and Issue: unknown, P. 134637 - 134637

Published: April 1, 2025

Language: Английский

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Regiodivergent Synthesis of 4,5′- and 4,4′-Imidazolinyl Spiropyrazolones from 4-Alkylidene Pyrazolones and Amidines

Organic Letters, Journal Year: 2021, Volume and Issue: 23(14), P. 5305 - 5310

Published: July 2, 2021

The solvent-free reaction of 4-alkylidene pyrazolones with amidines can furnish 4,5′-imidazolinyl spiropyrazolones in good to excellent yields when promoted by N-iodosuccinimide under ball-milling conditions, whereas it almost exclusively affords 4,4′-imidazolinyl if mediated N-bromosuccinimide heated toluene. On the basis this switchable cyclization strategy, a powerful metal-free method for regioselective and diastereoselective synthesis structurally diverse 4,5′- has been successfully developed.

Language: Английский

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Squaramide Catalyzed Asymmetric Synthesis of Five‐ and Six‐Membered Rings

Asian Journal of Organic Chemistry, Journal Year: 2021, Volume and Issue: 10(6), P. 1345 - 1376

Published: April 19, 2021

Abstract Chiral analogues of squaramides have been fruitful in organocatalyzed asymmetric reactions over last decade. Alongside other H‐bonding catalysts like ureas, thioureas: proved to be efficient for the formation acyclic and cyclic chiral molecules. A wide range molecules bearing multiple functionalities stereocenters synthesized by using several bifunctional as catalysts. These perform base utilizing basic N atom their extension help stereoinduction forming H‐bonds with suitable H‐bond acceptors. The present review focuses on assembling recent progresses synthesis five six membered rings promoted squaramides. handful articles published research groups documenting construction five‐ six‐membered part interesting complex molecular architectures. Different methodologies conventional formal cycloadditions or cascade engineered through assistance fabricate carbo‐ heterocycles. This also includes dual cooperative catalytic system which squaramide is one

Language: Английский

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Diversity-Oriented Synthesis of Spiropentadiene Pyrazolones and 1H-Oxepino[2,3-c]pyrazoles from Doubly Conjugated Pyrazolones via Intramolecular Wittig Reaction

Organic Letters, Journal Year: 2020, Volume and Issue: 22(12), P. 4760 - 4765

Published: June 9, 2020

An efficient method for the diversity-oriented synthesis of spiropentadiene pyrazolones and 1H-oxepino[2,3-c]pyrazoles is reported. The methodology attributes O-acylation phosphorus zwitterions which were formed by a tandem phospha-1,6-addition PBu3 to α,β,γ,δ-unsaturated pyrazolones, further generating betaine intermediates that preferentially resulted in aforementioned cyclic products manner. mechanistic investigations revealed formation betaines key step provide via an intramolecular Wittig reaction or unprecedented δ-C-acylation/cyclization/Wittig reaction.

Language: Английский

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Enantioselective synthesis of functionalized 1,4-dihydropyrazolo-[4′,3′:5,6]pyrano[2,3-b]quinolines through ferrocenyl-phosphine-catalyzed annulation of modified MBH carbonates and pyrazolones

Chemical Communications, Journal Year: 2021, Volume and Issue: 57(38), P. 4690 - 4693

Published: Jan. 1, 2021

An enantioselective synthesis of 1,4-dihydropyrazolo[4′,3′:5,6]pyrano[2,3-b]quinolines from modified MBH carbonates and pyrazolones via a chiral phosphine-mediated alkylation/annulation sequence has been realized.

Language: Английский

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NIS-Promoted Chemodivergent and Diastereoselective Synthesis of Pyrrolinyl and Cyclopentenyl Spiropyrazolones via Regulated Cyclization of Alkylidene Pyrazolones with Enamino Esters

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(12), P. 9051 - 9055

Published: May 30, 2024

An N-iodosuccinimide-promoted annulation of alkylidene pyrazolones with enamino esters has been explored to construct a spiropyrazolone moiety through Michael addition/iodination/intramolecular nucleophilic substitution sequence. When the reaction was performed in acetonitrile at 100 °C, it furnished pyrrolinyl spiropyrazolones exclusively an anti configuration N-attacking cyclization. dimethyl sulfoxide 80 °C presence K2HPO4, afforded cyclopentenyl syn C-attacking A plausible mechanism also proposed.

Language: Английский

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