Photochemical and Electrochemical Synthesis of Oxazoles and Isoxazoles: An Update

Advanced Synthesis & Catalysis, Journal Year: 2024, Volume and Issue: 366(10), P. 2186 - 2208

Published: April 4, 2024

Abstract This review presents an outline of current advancements in the photochemical and electrochemical synthesis oxazoles isoxazoles. Oxazole isoxazole are important building blocks for a variety medicinally useful compounds. Therefore, these heterocycles via sustainable technologies is worth demanding. Photochemical two among few technologies. covers brief discussion on reaction parameters like catalysts, substrates scope, temperature, solvents, electrodes, electrolytes (in case process), light source process) individual reaction. Detailed mechanistic insight each also presented. Finally, summary, future direction toward development effective methods isoxazoles

Language: Английский

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Divergent Electrochemical Synthesis of Indoles through pK_a Regulation of Amides: Synthetic and Mechanistic Insights

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(20)

Published: Jan. 31, 2024

A divergent synthetic approach to access highly substituted indole scaffolds is illustrated. By virtue of a tunable electrochemical strategy, distinct control over the C-3 substitution pattern was achieved by employing two analogous 2-styrylaniline precursors. The chemoselectivity governed fine-tuning acidity amide proton, relying on appropriate selection N-protecting groups, and assisted reactivity electrogenerated intermediates. Detailed mechanistic investigations based cyclic voltametric experiments computational studies revealed crucial role water additive, which assists proton-coupled electron transfer event for acidic precursors, followed an energetically favorable intramolecular C-N coupling, causing exclusive fabrication unsubstituted indoles. Alternatively, implementation cationic olefin activator delivers indoles through preferential nucleophilic nature N-acyl amides. This judicious groups regulate pK

Language: Английский

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Modern Cyclopropanation via Non‐Traditional Building Blocks

ChemCatChem, Journal Year: 2024, Volume and Issue: 16(14)

Published: March 13, 2024

Abstract Small, strained carbocyclic systems have fascinated organic chemists from both a theoretical and synthetic standpoint. These often challenge conventional wisdom when it comes to molecular structure tactics for chemical construction. The cyclopropyl motif is one such ring system that remains at the forefront of method development in modern era. With advent an array non‐traditional building blocks, range new cyclopropanation processes using one‐ two‐electron strategies been developed not only overcome shortcomings classical approaches but also provide entry into wide classes cyclopropanes. This review discusses recent advances this area with emphasis on their mechanistic underpinnings potential applications. Additionally, concise overview properties traditional cyclopropanes provided.

Language: Английский

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Electrochemical Oxidation Enables Regioselective 1,3-Hydroxyfunctionalization of Cyclopropanes

Organic Letters, Journal Year: 2023, Volume and Issue: 25(33), P. 6178 - 6183

Published: Aug. 16, 2023

The direct construction of 1,3-hydroxyfunctionalized molecules is still a significant challenge, as they can currently be obtained through multiple synthetic steps. Herein, we report general and efficient 1,3-hydroxyfunctionalization arylcyclopropanes by electrochemical oxidation with strategic choice nucleophiles H2O. 1,3-Amino alcohols, 1,3-alkynyl 1,3-hydroxyesters, 1,3-halo alcohols are achieved high levels chemo- regio-selectivity, opening new dimension for 1,3-difunctionalization reaction.

Language: Английский

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Electrochemical Formation of Oxazolines by 1,3-Oxyfluorination of Non-activated Cyclopropanes

Organic Letters, Journal Year: 2024, Volume and Issue: 26(11), P. 2158 - 2162

Published: March 8, 2024

The C–C bond in non-activated cyclopropanes can be intramolecularly cleaved with an electrochemically generated amidyl radical forming oxazolines. In the presence of TBABF4, this provides 1,3-oxyfluorination products. cleavage cyclopropane proceeds inversion configuration, suggesting intramolecular homolytic substitution (SHi) mechanism. performance TBABF4 as efficient fluoride source was explained by accumulation BF4– anion at anode surface, which a carbocation is formed oxidation C-centered radical.

Language: Английский

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Electrochemical Synthesis of Sulfonamide Derivatives: Electrosynthesis Conditions and Reaction Pathways

ChemElectroChem, Journal Year: 2024, Volume and Issue: 11(10)

Published: Feb. 15, 2024

Abstract In 2014, the World Health Organization called drug resistance to antibiotics a “major global threat”. Therefore, ever‐increasing human need for new with greater effectiveness and fewer side effects is necessity. Meanwhile, sulfonamides are among most widely used in world. this review, attention has been paid key points raised various papers field of electrosynthesis these compounds, considering their positive negative aspects, including interaction as much possible principles green chemistry absence environmental risks, low cost versatility scalability method along acceptable efficiency. following, we will discuss research focused on synthesis sulfonamide derivatives based oxidation or reduction compounds which take place working electrode surface.

Language: Английский

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Electrochemical Ring Opening and [3 + 2] Cycloaddition of Aziridines: Access to 1,2-Bifunctionalized Products and Imidazolines

Organic Letters, Journal Year: 2025, Volume and Issue: 27(4), P. 989 - 994

Published: Jan. 21, 2025

Herein, we report an electricity-driven activation of aziridine via direct anodic oxidation to give N-heterocycles and 1,2-bifunctionalized products by excluding any oxidant/reductant or metal catalyst. Many structurally modified aziridines were employed in the presence different nitriles. A large variety nucleophiles screened furnish chemoselectively O-alkylated C-alkylated products. Late-stage derivatization with natural medicinally active compounds has also been done. Remarkably, our strategy was found be a greener, sustainable, atom-economical approach (E-factor = ca. 0.8). Azetidine compatible protocol generated six-membered N-heterocycles. The detailed mechanistic study highlighted that reaction is driven generation radical cation followed SN2 nucleophilic attack.

Language: Английский

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Strain-Releasing Hydrogenation of Donor–Acceptor Cyclopropanes and Cyclobutanes via Electrochemical Site Selective Carbonyl Reduction

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

Published: April 21, 2025

An acid or hydrogen gas-free electrochemical protocol is established for the hydrogenation of strained rings (cyclopropane and cyclobutane) at room temperature atmospheric pressure. The mechanistic study revealed that reaction was initiated via reduction carbonyl group. methodology highly specific toward such as cyclopropane cyclobutane, which exhibit broad functional group tolerance.

Language: Английский

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Electrochemical Oxidative Dearomatization Strategy for Accessing Spiro[4.5]dienones and Derivatives

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(4), P. 2200 - 2211

Published: Feb. 8, 2024

Electrochemical dearomatization has been recognized as an attractive tool for the rapid construction of structurally diverse molecules. The designed methodology encompasses eco-friendly and efficient electrochemical approach to synthesizing spiro[4.5]dienones under mild reaction conditions. Furthermore, detailed mechanistic studies strongly bolster our hypothesis emphasize role HFIP in mechanism. protocol is scalable showcases a broad substrate scope with tolerance toward numerous functional groups. Henceforth, this strategy can be deployed alternative sustainable accessing spiro[4.5]dienones.

Language: Английский

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Sacrificial Anode-Free Electrochemical Cross-Electrophile Coupling of 1,3-Diol Derivatives to Form Aliphatic and Aryl Cyclopropanes

Organic Letters, Journal Year: 2024, Volume and Issue: 26(31), P. 6556 - 6561

Published: July 31, 2024

Cross-electrophile coupling reactions that forge C(sp3)–C(sp3) bonds are strategic methods for the synthesis of molecules with high F(sp3), yet very few employ electrochemical conditions as necessary reductant. Herein, we report an intramolecular cross-electrophile reaction 1,3-diol derivatives to access aliphatic and aryl cyclopropanes, including spirocyclic fused bicyclic cyclopropanes. The scalable (eXEC) employs a nonsacrificial anode in undivided cell.

Language: Английский

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