Advances in catalytic enantioselective synthesis of chiral helicenes and helicenoids

Chem Catalysis, Год журнала: 2022, Номер 2(11), С. 3077 - 3111

Опубликована: Ноя. 1, 2022

Язык: Английский

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

Nature Communications, Год журнала: 2023, Номер 14(1)

Опубликована: Июнь 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.

Язык: Английский

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

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(9)

Опубликована: Янв. 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.

Язык: Английский

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Divergent asymmetric synthesis of heterohelicenes via sequential organocatalyzed Povarov reaction and aromatization

Cell Reports Physical Science, Год журнала: 2024, Номер 5(6), С. 101993 - 101993

Опубликована: Май 27, 2024

Incorporating main-group elements into the backbone of chiral carbohelicenes can significantly alter their electronic and optical properties, which renders asymmetric synthesis heterohelicenes an appealing research field. Herein, we present divergent two distinct types from same starting material by employing key Povarov reaction with phosphoric acid catalysts. Specifically, one-pot reaction/oxidative aromatization yielded C1-ortho-phenol-substituted [5]/[6]pyridohelicenes, while subsequent Pd(II)/base-mediated furan formation resulted in longer [7]/[8]heterohelicenes bearing both pyridine moieties. Fruitful derivatizations helicenes, along promising photophysical chiroptical have underscored value this method.

Язык: Английский

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Palladium-Catalyzed Modular Synthesis of Enantioenriched Pyridohelicenes through Double Imidoylative Cyclization

ACS Catalysis, Год журнала: 2022, Номер 12(20), С. 13034 - 13041

Опубликована: Окт. 12, 2022

Enantioenriched pyrido[6]helicenes and furan-containing pyrido[7]helicenes have been synthesized through palladium-catalyzed double imidoylative cyclization by applying axially achiral multiaryl bisisocyanides aryl iodides as coupling components. Two pyridyl rings were constructed sequentially forming four C–C bonds in one pot with low catalyst loading. A control study using precyclized biaryl monoisocyanides revealed the second pyridine-forming enantiomer-generating step, which also enabled introduction of different substituents, including trifluoromethyl, on helical skeleton. This general convergent approach to structurally diversified optically pure pyridohelicenes paves way for optical studies potential applications this important class azahelicenes.

Язык: Английский

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Divergent Aromatization of α-Halobenzyl γ-Butenolides Initiated by Selective Enol Protonation to Benzo[c]fluorenones and Naphthalenes

The Journal of Organic Chemistry, Год журнала: 2024, Номер 89(15), С. 11067 - 11071

Опубликована: Июль 23, 2024

An unprecedented divergent aromatization reaction of α-halobenzyl γ-butenolides has been described for the selective and concise synthesis highly substituted benzo higher π-extended fluorenones, 1,3-disubstituted naphthalenes depending on migration ability quaternary α-substituent. This switch from Ag

Язык: Английский

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Recent development of azahelicenes showing circularly polarized luminescence

Chemical Communications, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

This feature article summarizes the recent developments of azahelicenes showing circularly polarized luminescence.

Язык: Английский

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Modulating the Embedding Position of Nitrogen Atom in [5]Helicene:the Design of Hot-Exciton Materials

Journal of Luminescence, Год журнала: 2025, Номер unknown, С. 121328 - 121328

Опубликована: Май 1, 2025

Язык: Английский

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Synthesis of Closed‐Heterohelicenes Interconvertible between Their Monomeric and Dimeric Forms

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(50)

Опубликована: Окт. 26, 2023

Oxidative fusion reaction of cyclic heteroaromatic pentads consisting pyrrole and thiophene gave closed-heterohelicene monomers dimers depending on the oxidation conditions. Specifically, with [bis(trifluoroacetoxy)iodo]benzene (PIFA) closed-[7]helicene connected at β-position one units remarkably elongated C-C bonds about 1.60 Å. Although this bond was intact against thermal physical activations, homolytic dissociation took place in DMSO upon irradiation UV light to give corresponding monomers. Thus, interconversion between closed-helicene monomer dimer achieved. The optically pure photo-dissociated into associated a turn-on circularly polarized luminescence (CPL).

Язык: Английский

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Synthesis of Aza[n]helicenes (n = 4–7) via Photocyclodehydrochlorination of 1-Chloro-N-aryl-2-naphthamides

The Journal of Organic Chemistry, Год журнала: 2022, Номер 87(11), С. 7150 - 7166

Опубликована: Май 12, 2022

A series of aza[n]helicenes (n = 4-7) was synthesized using a photocyclodehydrochlorination 1-chloro-N-aryl-2-naphthamides as general synthetic procedure introducing the nitrogen atom to third ring helicene framework. The effect presence in skeleton on physicochemical properties prepared studied and compared those parent carbo-analogues. insertion into outer edge molecule has severe impact certain such optical rotation, electrostatic potentials, intermolecular interactions. On other hand, some UV/vis, fluorescence, phosphorescence spectra remained almost unaffected when carbohelicenes. can be also used for further derivatization, which lead modification properties, manifested here fluorescence changes induced by protonation.

Язык: Английский

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