Arylation of α‐Imino Ketones and their Cyclization with Allenoates: Direct Access to Sterically Hindered Pyrroles

Asian Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 28, 2025

Abstract Herein, we report a calcium‐catalyzed, one‐pot, four‐component reaction to synthesize diversely substituted pyrroles. This atom‐economy involves sequence of reactions that proceed via in situ formation α ‐ imino ketones, Friedel‐Crafts arylation, aza‐cyclization, and aromatization the single pot. The showed broad substrate scope with good yields. We demonstrated gram‐scale synthesis post‐synthetic modifications.

Language: Английский

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Portable fluorogenic probe for monitoring of volatile amine vapour and food spoilage

Chinese Chemical Letters, Journal Year: 2023, Volume and Issue: 35(3), P. 108579 - 108579

Published: May 19, 2023

Language: Английский

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Recent advances in annulations enabled by nucleophilic Lewis base/metal dual catalysis

Chinese Chemical Letters, Journal Year: 2023, Volume and Issue: 34(10), P. 108544 - 108544

Published: May 15, 2023

Language: Английский

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Recent Advances in Nucleophilic Lewis Base‐Catalyzed Cycloadditions for Synthesis of Spirooxindoles

Advanced Synthesis & Catalysis, Journal Year: 2023, Volume and Issue: 365(24), P. 4412 - 4439

Published: Nov. 16, 2023

Abstract Spirooxindoles are privileged scaffolds in diverse bioactive natural products and pharmaceuticals, significant achievements for the construction of these molecules have thus been made past years. Among them, organocatalysis, particular, nucleophilic Lewis base catalysis, has recently emerged as an efficient reliable method preparation valuable functionalized spirooxindoles. According to different kinds catalysts, we summarize classify three catalytic strategies; tertiary amine‐catalyzed cycloadditions, NHC‐catalyzed phosphine‐catalyzed respectively. Through methods, potential spirooxindole skeletons owning various functional groups can be produced enrich small organic molecule library. In this review, describe a comprehensive updated advances cycloaddition reactions Meanwhile, related mechanism application annulation strategies product total synthesis will highlighted detail.

Language: Английский

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Streptocyanine as an activation mode of amine catalysis for the conversion of pyridine rings to benzene rings

Chemical Science, Journal Year: 2022, Volume and Issue: 14(3), P. 485 - 490

Published: Dec. 21, 2022

We report conjugated methine compounds generated from N -arylpyridiniums and amines; streptocyanines can be used as a new activation mode for amine catalysis applied to the conversion of pyridine rings benzene rings.

Language: Английский

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Palladium-catalyzed asymmetric (4 + 3) cycloaddition of N-2,2,2-trifluoroethylisatin ketimines: access to optically active spirooxindoles

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(11), P. 2648 - 2652

Published: Jan. 1, 2023

Herein, we disclose the first Pd-catalyzed enantioselective (4 + 3) cycloaddition of N -2,2,2-trifluoroethylisatin ketimines with 2-methylidenetrimethylene carbonate.

Language: Английский

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DBU-Catalyzed Ring Expansion or Ene-amine Formation Involving δ-Acetoxy Allenoates and N-Sulfonyl Hydrazides

Organic Letters, Journal Year: 2023, Volume and Issue: 25(20), P. 3713 - 3717

Published: May 15, 2023

DBU-catalyzed spiro-annulation and concomitant ring expansion/domino reaction of δ-acetoxy allenoates with cycl-2-ene-N-sulfonyl hydrazides afford ring-expanded (5 → 6, 6 7, 7 8) products. By contrast, cycl-3-ene/ane-N-sulfonyl hydrazones under similar conditions deliver pyrazole cores the same allenoate that involves allylic elimination in which serves as 3C-synthon. The key spirocyclic intermediates, well dienyl-amine are isolated characterized. An extension to (R)-(-)-carvone-derived sulfonyl hydrazide also led expansion gave pyrazoloazepine.

Language: Английский

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δ-Acetoxy Allenoate as a 5C-Synthon in Domino-Annulation with Sulfamidate Imines: Ready Access to Coumarins

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 88(17), P. 12432 - 12444

Published: Aug. 21, 2023

A DMAP-catalyzed sequential benzannulation and lactonization strategy in which δ-acetoxy allenoate functions as a 5C-synthon its reaction with cyclic sulfamidate imines is reported. This platform delivers π-extended coumarin frameworks under metal-free conditions via allylic elimination followed by Mannich coupling, proton shifts, C-N bond cleavage, key steps. The driving force for this domino the formation of diene-ammonium intermediate O-S cleavage. ESI-HRMS has been useful gaining insights into pathway.

Language: Английский

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Tertiary‐Amine Controlled (3+3) or (4+2) Annulations of β′‐Acetoxy Allenoates with N‐Sulfonyl Ketimines: An Entry to m‐Teraryl and Fused Dihydropyridines

Advanced Synthesis & Catalysis, Journal Year: 2024, Volume and Issue: 366(5), P. 1165 - 1175

Published: Jan. 10, 2024

Abstract Lewis base dependent (3+3) and (4+2) annulations of β′ ‐acetoxy allenoates with N ‐sulfonyl ketimines offer m ‐teraryl fused dihydropyridines varying substituents depending on the tertiary amine as well subtle changes in reaction conditions. The triazabicyclodecene (TBD)‐catalyzed annulation involves 1,2‐elimination followed by 6‐ endo ‐dig cyclization key steps delivering 1,4‐hydropyridines. same reactants under DMAP catalysis via Mannich coupling, rather than C−N bond cleavage/aromatization. Key intermediates have been identified HRMS studies.

Language: Английский

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Highly stereo- and enantio-selective synthesis of spiro- cyclopropyl oxindoles via organic catalyst-mediated cyclopropanation

Chinese Chemical Letters, Journal Year: 2025, Volume and Issue: unknown, P. 110923 - 110923

Published: Feb. 1, 2025

Language: Английский

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