Aminocatalytic, Stereoselective Synthesis of Tetrahydrocarbazole Spiropyrazolones via Remote [4 + 2] Annulation of Indole Tethered Enal With Olefinic Pyrazolones

ChemistrySelect, Journal Year: 2025, Volume and Issue: 10(5)

Published: Feb. 1, 2025

Abstract We present the first application of olefinic pyrazolone in conjunction with indole‐tethered enal an aminocatalytic remote [4 + 2] annulation reaction, successfully yielding tetrahydrocarbazole spiropyrazolone frameworks moderate to good yields, accompanied by significant enantio‐ and diastereoselectivities. The robustness this developed protocol is demonstrated through generation a diverse array 22 examples, all exhibiting consistent yields stereoselectivities. Furthermore, we achieved gram‐scale synthesis synthesized biologically relevant fluorohexahydrofuranocarbazole via two‐pot, three‐step sequence involving 2]‐addition, reduction, fluoroetherification reactions. Finally, propose plausible mechanism, supported SC‐XRD NOE experiments, highlighting crucial aspect research.

Language: Английский

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Blossoming of Polyenamine Catalysis in Asymmetric Synthesis: Scope and Future Applications

Chemistry - An Asian Journal, Journal Year: 2023, Volume and Issue: 18(14)

Published: May 22, 2023

After the emergence of organocatalysis, field asymmetric synthesis has reached an exceptional level in this century. Asymmetric aminocatalysis, among other organocatalytic strategies, proceeded through LUMO-lowering iminium ion and HOMO-raising enamine activation appeared as a powerful synthetic approach for realizing potential chiral building blocks from unmodified carbonyl compounds. Consequently, concept strategy plethora transformations based on enamine, dienamine, most recently trienamine, tetraenamine, pentaenamine catalysis been devised. In mini-review article, we disclosed recent progress accomplished aminocatalysis polyenamine strategies functionalization compounds, covered reports 2014 to till date.

Language: Английский

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Enantioselective Synthesis of Octahydrofuranoindole Core of Aspidosperma Alkaloids via a Diels‐Alder/Reduction/Fluoroetherification Reaction Sequence

Chemistry - An Asian Journal, Journal Year: 2023, Volume and Issue: 18(16)

Published: July 7, 2023

Abstract Herein, we disclose the enantioselective synthesis of novel tricyclic fluorooctahydrofuranoindole spirooxindoles bearing five contiguous stereocenters via an organocatalytic sequential Diels‐Alder/Reduction/Fluoroetherifiction reaction strategy. The potential developed approach was witnessed by generating vast examples (up to 20 examples) library molecules embedding natural product core with good yields and phenomenal diastereo‐ enantioselectivities 77 % overall yield, up 99 ee 10 : 1 dr). synthetic utility our protocol further demonstrated synthesizing iodooctahydroindole spirooxindole framework through Diels‐Alder/reduction/iodoetherification in 65 yield excellent stereoselectivity (99 4

Language: Английский

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N-2,2,2-Trifluoroethylisatin ketimine as a 1,2-dipolarophile for [3 + 2]-addition to access optically pure spirothiazolidine oxindoles

Organic & Biomolecular Chemistry, Journal Year: 2023, Volume and Issue: 21(24), P. 4972 - 4976

Published: Jan. 1, 2023

The first report on using N-2,2,2-trifluoroethylisatin ketimine as a 1,2-dipolarophile for [3 + 2]-addition and the asymmetric synthesis of N-2,2,2-trifluoroethylspirothiazolidine oxindoles is described. organocatalyzed reaction with 1,4-dithiane-2,5-diol provided an array (up to 25 examples) in excellent yield, enantioselectivity, diastereoselectivity 96% 99% ee, 99 : 1 dr). In addition, synthetic utility developed methodology has been demonstrated by transforming optically pure spirothiazolidine into medicinally important spirothiazolidinone spirothiazolidinone-S-oxide.

Language: Английский

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Amine Catalyzed Remote [4+2]‐annulation Of Indole Tethered Enal And Oxindole Olefin To Access Optically Pure Hydrocarbazole Spirooxindole Scaffolds

Asian Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 13(6)

Published: Feb. 19, 2024

Abstract This research showcases a methodology for crafting highly intricate hydrocarbazole spirooxindole frameworks endowed with three consecutive stereocenters. Achieved through trienamine‐catalyzed remote [4+2]‐annulation reaction, the method's significance is underscored by synthesizing an extensive array of library molecules (up to 27 examples). These compounds mimic natural products, exhibit good yields 85 %), exceptional diastereo‐, enantiomeric ratios 17 : 1 dr , 99.9 0.1 er ). The practicality our strategy further exemplified successfully hexahydroepoxyethanocarbazole scaffold via sequential [4+2]‐annulation/‐reduction/epoxidation‐cyclization achieving 75 % overall yield, maintaining excellent stereoselectivity (99.5 0.5

Language: Английский

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Asymmetric Synthesis of spiro[benzofuran-pyrrolidine]-indolinedione via Bifunctional Urea Catalyzed [3+2]-annulation Reaction

Organic & Biomolecular Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 3, 2024

Herein, we demonstrate the first employment of ( E )-alkylidine benzofuran-2-one for high enantio- and diastereoselective construction trifluormethylated spiro[benzofuran-pyrrolidine]indolinedione.

Language: Английский

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Recent strategies in the synthesis of spirooxindole scaffolds (stereoselective synthesis)

Elsevier eBooks, Journal Year: 2024, Volume and Issue: unknown, P. 239 - 264

Published: Jan. 1, 2024

Language: Английский

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