Atroposelective Synthesis of Axially Chiral Naphthylpyrroles by a Catalytic Asymmetric 1,3-Dipolar Cycloaddition/Aromatization Sequence

Organic Letters, Journal Year: 2024, Volume and Issue: 26(4), P. 922 - 927

Published: Jan. 24, 2024

A straightforward methodology for the enantioselective preparation of axially chiral 2-naphthylpyrroles has been developed. This protocol is based on a CuI/Fesulphos-catalyzed highly 1,3-dipolar cycloaddition an azomethine ylide followed by pyrrolidine alkylation and to pyrrole oxidation. The mild conditions employed in DDQ/blue light-mediated aromatization process facilitate effective central-to-axial chirality transfer affording corresponding pyrroles with high atroposelectivity.

Language: Английский

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Hydrosulfonylation of Alkynes for Stereodivergent Synthesis of Vinyl Sulfones: Synthetic Strategy and Mechanistic Insights

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(21), P. 14816 - 14828

Published: May 16, 2024

Direct synthesis of thermodynamically less favorable (Z)-vinyl sulfones presents a notable challenge in organic synthesis. In addition, the development stereodivergent for (E)- and is crucial but remains elusive. this study, we present hydrosulfonylation aryl-substituted alkynes, achieving by leveraging both thermodynamic kinetic controls. Notably, challenging was achieved through kinetically controlled process without need catalyst. To synthesize (E)-vinyl sulfones, unconventional visible light-mediated isomerization employed as means facilitating transition to favored form. The study encompasses comprehensive experimental computational investigation, which provides valuable insights into reaction mechanism. This investigation reveals two plausible pathways: novel double spin-flip mechanism hydrogen atom transfer presence eosin Y. not only advances our understanding mechanisms beyond conventional energy-transfer routes also offers robust switchable strategy synthesizing thereby providing versatile avenue creation compounds fields medicinal chemistry.

Language: Английский

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Decarboxylative 1,3-dipolar cycloadditions of l-proline

RSC Advances, Journal Year: 2024, Volume and Issue: 14(12), P. 8481 - 8501

Published: Jan. 1, 2024

1,3-Dipolar cycloaddition is one of the important chemical reactions between a 1,3-dipole and dipolarophile to construct five-membered heterocyclic compound. As an available α-amino acid reactant, l-proline extensively used in 1,3-dipolar reactions. A diverse spectrum bioactive spiro fused N-heterocycles obtained through this synthetic approach. In review, we have described use synthesis various spiro- scaffolds.

Language: Английский

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Catalytic Schmittel-Type [2+2] Cycloaddition of γ-Alkynyl Diazoacetates with Terminal Alkynes for Accessing Cyclobuta[a]indenes

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: March 17, 2025

Instead of the conventional [4+2] cycloaddition, a regioselective Schmittel-type [2+2] cycloaddition yne–allene esters, generated in situ from copper-catalyzed dediazotized coupling γ-alkynyl diazoacetates with terminal alkynes, is reported, enabling bicyclization process to produce diverse array C1-arylated cyclobuta[a]indenes moderate good yields. The protocol features wide functional group compatibility, mild reaction conditions, and experimental simplicity, holding significant potential for building new tricyclic cyclobutenes.

Language: Английский

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Reflexive Chirality Transfer (RCT): Asymmetric 1,3-Dipolar Cycloaddition of α-Amino Acid Schiff Base with Nonchiral Copper Catalyst

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: April 1, 2025

Although optically pure α-amino acids are ubiquitous, their chirality is usually lost during the α-C-H deprotonation. Consequently, precious chiral catalysis has been necessary to synthesize active α-tetrasubstituted unnatural acid derivatives, even when starting with acids. However, here, we report a catalytic asymmetric 1,3-dipolar cycloaddition that preserves α-carbon of derivatives. This process directly converts readily available Schiff bases into pyrrolidine derivatives without external additives, despite temporary loss through formation planar 1,3-dipole intermediates. Mechanistic studies revealed base transiently transferred metal-centered in enolates and subsequently restored as carbon-centered products. conceptually novel "reflexive transfer (RCT)" strategy offers simple cost-effective approach addressing current limitations pool synthesis.

Language: Английский

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Engaging Isatins and Amino Acids in Multicomponent One-Pot 1,3-Dipolar Cycloaddition Reactions—Easy Access to Structural Diversity

Molecules, Journal Year: 2023, Volume and Issue: 28(18), P. 6488 - 6488

Published: Sept. 7, 2023

Multicomponent reactions (MCRs) have undoubtedly emerged as the most indispensable tool for organic chemists worldwide, finding extensive utility in synthesis of intricate natural products, heterocyclic molecules with significant bioactivity, and pharmaceutical agents. The multicomponent one-pot 1,3-dipolar cycloaddition reactions, which were initially conceptualized by Rolf Huisgen 1960, find application contemporary chemistry. In terms green synthesis, is highly favored owing to its numerous advantages, including high step- atom-economies, remarkable product diversity, well excellent efficiency diastereoselectivity. Among pieces research, fascinating reaction involves utilization azomethine ylides generated from isatins amino acids that can be captured various dipolarophiles. This approach offers a efficient convenient method constructing spiro-pyrrolidine oxindole scaffolds, are crucial building blocks biologically active molecules. Consequently, this review delves deeper into dipolarophiles utilized over past six years.

Language: Английский

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Dipolarophile‐Steered Formal Stereodivergent Synthesis of 2,5‐cis/trans‐Pyrrolidines Based on Asymmetric 1,3‐Dipolar Cycloaddition of Imino Lactones

Chemistry - A European Journal, Journal Year: 2023, Volume and Issue: 29(66)

Published: Sept. 11, 2023

The stereodivergent asymmetric synthesis of 2,5-trans/cis pyrrolidines by 1,3-dipolar cycloaddition using two different types activated alkenes is described. When ylidene-isoxazolones were employed as dipolarophiles, the Ag/(S,Sp )-iPr-FcPHOX-catalyzed [3+2] imino lactones proceeded with 2,5-trans selectivity. Subsequent decarboxylation isoxazolone rings produced stereoretention. In reaction acyclic enones alkenes, Ag/(R,Sp )-ThioClickFerrophos complex-catalyzed afforded 2,5-cis substituted in high yields and enantioselectivities. Therefore, these methods can be considered a formal 2,5-cis/trans pyrrolidines.

Language: Английский

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Metal‐Free Electrochemical [3+2] Cycloaddition between α‐Amino Carbonyls and Tosylmethyl Isocyanide en route to Substituted Imidazoles

Advanced Synthesis & Catalysis, Journal Year: 2023, Volume and Issue: 366(2), P. 241 - 247

Published: Nov. 24, 2023

Abstract The established strategy unveils a metal and mediator‐free electrochemical [3+2] cycloaddition approach among α ‐amino carbonyls tosylmethyl isocyanide (TosMIC) fabricating substituted imidazole scaffolds. Implementation of electro‐redox conditions on this eliminates the essential requirement transition catalysts chemical oxidants. A wide variety different functionalities are well tolerated under reaction condition, contributing to substrate scope applicability. Several control experiments cyclic voltammetry studies suggest an electro‐oxidation triggered successive C−C C−N bond formations followed by rapid aromatization for constructing five‐membered core structure.

Language: Английский

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Asymmetric Metal‐Templated Approach to Amino Acids with a CF₃‐Containing 3,2’‐Pyrrolidinyl Spirooxindole Core via a Michael/Mannich [3+2]‐Cycloaddition Reaction

Advanced Synthesis & Catalysis, Journal Year: 2023, Volume and Issue: 366(5), P. 1205 - 1211

Published: Dec. 12, 2023

Abstract We report here a practical protocol for the asymmetric synthesis of amino acids (AAs) with CF 3 ‐containing 3,2’‐pyrrolidinyl spirooxindole skeleton three defined carbon stereocenters via sequential Michael/Mannich [3+2]‐cycloaddition reaction. The coupling robust and stereochemically stable chiral dehydroalanine Ni(II) complex various N ‐2,2,2‐trifluoroethylisatin ketimines in presence triethylamine afforded library single diastereomeric complexes moiety 36–71% yields. In particular, change base to LiOH allowed obtain predominantly Michael addition product 76% yield. Finally, decomposition obtained HCl provided target AA core (2 S ,4 R )‐2,4‐diamino‐5,5,5‐trifluoropentanoic acid – an ( )‐norvaline derivative, together easy recovery auxiliary ligand starting complex.

Language: Английский

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Annulations involving p-benzoquinones: stereoselective synthesis of fused, spiro and bridged molecules

New Journal of Chemistry, Journal Year: 2024, Volume and Issue: 48(18), P. 8243 - 8276

Published: Jan. 1, 2024

The present review summarizes the recent advances (2018–2023) in stereoselective annulation involving p -benzoquinones for construction of fused, spiro and bridged/cage frameworks.

Language: Английский

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