Enantioselective synthesis of chiral quinohelicenes through sequential organocatalyzed Povarov reaction and oxidative aromatization

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: June 8, 2023

Heterohelicenes are of increasing importance in the fields materials science, molecular recognition, and asymmetric catalysis. However, enantioselective construction these molecules, especially by organocatalytic methods, is challenging, few methods available. In this study, we synthesize enantioenriched 1-(3-indol)-quino[n]helicenes through chiral phosphoric acid-catalyzed Povarov reaction followed oxidative aromatization. The method has a broad substrate scope offers rapid access to an array quinohelicenes with enantioselectivities up 99%. Additionally, photochemical electrochemical properties selected explored.

Language: Английский

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Helicoselective Synthesis of Indolohelicenoids through Organocatalytic Central‐to‐Helical Chirality Conversion

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(9)

Published: Jan. 10, 2024

We report the helicoselective and convergent construction of indolohelicenoids with excellent efficiency stereocontrol. This reaction proceeds through a chiral-phosphoric-acid-catalyzed enantioselective cycloaddition eliminative aromatization sequence, which can be finely controlled by adjusting temperature. Mechanistic studies reveal that chiral phosphoric acid cooperatively serves as both bifunctional Brønsted catalyst, enabling one-pot central-to-helical chirality conversion. Additionally, optical properties synthesized were characterized to explore their potential applications in organic photoelectric materials.

Language: Английский

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Recent advances of Cp*Ir complexes for transfer hydrogenation: focus on formic acid/formate as hydrogen donors

Organic & Biomolecular Chemistry, Journal Year: 2023, Volume and Issue: 21(37), P. 7484 - 7497

Published: Jan. 1, 2023

This review summarise the transfer hydrogenation of C=O, C=C, C=N bonds unsaturated substrates via Cp*Ir complexes as catalysts and formic acid/formate hydrogen sources.

Language: Английский

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Crystallization-Induced Chirality Transfer in Conformationally Flexible Azahelicene Au(I) Complexes with Circularly Polarized Luminescence Activation

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(18), P. 12463 - 12472

Published: April 16, 2024

Flexible and twisted annulated π-systems exhibit numerous unique desirable features, owing to their ability display chirality. However, preventing racemization due the dynamic nature of chirality remains a challenge. One promising approach stabilize homochirality in such systems is transfer from chiral auxiliary moiety displaying Herein, we introduce new for stabilization conformationally flexible azahelicene species via crystallization-induced intermolecular Au(I) complexes featuring (dibenzo[

Language: Английский

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Ni(II)-Catalyzed Transfer Hydrogenation of Azoarenes with NH₃BH₃

Organic Letters, Journal Year: 2023, Volume and Issue: 25(22), P. 4198 - 4202

Published: May 31, 2023

A nickel-catalyzed semihydrogenation of azoarenes to hydrazoarenes with NH3BH3 is developed. The catalytic system exhibits good functional group tolerance and a high turnover frequency at room temperature. Results control deuterium-labeling experiments indicate that the ethanol hydroxyl BH3 groups each donated one hydrogen this transfer hydrogenation, main byproducts were B(OEt)3 H2. Moreover, density theory calculations indicated reaction proceeded via ligand-to-ligand mechanism. This study presents novel nickel for azoarenes.

Language: Английский

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Iridium-Catalyzed Migratory Terminal C(sp³)–H Amidation of Heteroatom-Substituted Internal Alkenes via Olefin Chain Walking

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: unknown

Published: Oct. 31, 2023

Hydroamination facilitated by metal hydride catalysis is an appealing synthetic approach to access valuable nitrogen-containing compounds from readily available unsaturated hydrocarbons. While high regioselectivity can be achieved usually for substrates bearing polar chelation groups, the reaction involving simple alkenes frequently provides nonselective outcomes. Herein, we report iridium-catalyzed highly regioselective terminal C(sp3)-H amidation of internal utilizing dioxazolones as amino source via olefin chain walking. Most notably, this mechanistic motif double bond migration position operates not only with dialkyl-substituted including styrenes but also heteroatom-substituted olefins such enol ethers, vinyl silanes, and borons, thus representing first example methyl latter type through a nondissociative walking process.

Language: Английский

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Synthesis, photophysical and chiroptical properties of 9–cyano[7]helicene for OLED applications. A combined experimental and theoretical investigation

Journal of Materials Science Materials in Electronics, Journal Year: 2024, Volume and Issue: 35(7)

Published: March 1, 2024

Language: Английский

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Double [8]Helicene Featuring a Dibenzo[g,p]chrysene Core: Synthesis and Chiroptical Response

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

Published: May 2, 2025

Double [8]helicene 1, featuring a dibenzo[g,p]chrysene core, was synthesized via the Scholl reaction, and its structure unambiguously confirmed by single-crystal X-ray diffraction analysis of dicationic salt [1-Cl]2+·(SbCl6-)2. The compound exhibits red fluorescence with an emission maximum at 618 nm (λem) quantum yield 16.2%, highlighting potential in optoelectronic applications. Furthermore, circular dichroism (CD) circularly polarized luminescence (CPL) measurements reveal notable chiroptical activity, absorption dissymmetry factors |gabs| = 5.11 × 10-3 |glum| 7.1 10-4, respectively.

Language: Английский

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Pyrene bridged double[7]helicene embedded with a heptagonal ring

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(15), P. 3714 - 3725

Published: Jan. 1, 2023

The article explores the intricate relationship between chiroptical properties and molecular symmetry of pyrene-conjugated single double [7]helicene.

Language: Английский

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Synthesis and Chiroptical Properties of a Saddle-Shaped Quadruple Helicene with a Cyclooctatetrapyrrole Core

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

Published: March 28, 2025

A quadruple helicene with a cyclooctatetrapyrrole core was synthesized via simple Ullmann reaction. Its single-crystal structure exhibits saddle shape. The compound shows fluorescence emission λem = 575 nm and good chiroptical properties, including dissymmetric absorption factor (|gabs|) of 5.84 × 10–3 (|glum|) 1.21 10–2.

Language: Английский

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