Copper‐Catalyzed Dearomative 1,2‐Hydroamination

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(32)

Опубликована: Май 23, 2024

Catalytic olefin hydroamination reactions are some of the most atom-economical transformations that bridge readily available starting materials-olefins and high-value-added amines. Despite significant advances in this field over last two decades, formal nonactivated aromatic compounds remains an unsolved challenge. Herein, we report extension to π-systems by using arenophile-mediated dearomatization Cu-catalysis perform 1,2-hydroamination on arenes. This strategy was applied a variety substituted arenes heteroarenes provide general access structurally complex We conducted DFT calculations inform mechanistic understanding rationalize unexpected selectivity trends. Furthermore, developed practical, scalable desymmetrization deliver enantioenriched dearomatized products enable downstream synthetic applications. ultimately used dearomative efficiently synthesize collection densely functionalized small molecules.

Язык: Английский

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Aromatic C−H Hydroxylation Reactions with Hydrogen Peroxide Catalyzed by Bulky Manganese Complexes

Advanced Synthesis & Catalysis, Год журнала: 2021, Номер 363(15), С. 3783 - 3795

Опубликована: Фев. 25, 2021

Abstract The oxidation of aromatic substrates to phenols with H 2 O as a benign oxidant remains an ongoing challenge in synthetic chemistry. Herein, we successfully achieved catalyze C−H bond oxidations using series biologically inspired manganese catalysts fluorinated alcohol solvents. While introduction bulky substituents into the ligand structure catalyst favors alkylbenzenes, occurs at benzylic position ligands bearing electron‐rich substituents. Therefore, nature is key controlling chemoselectivity these Mn‐catalyzed oxidations. We show that groups prevents inhibition through phenolate‐binding, consequently providing higher catalytic turnover numbers for phenol formation. Furthermore, employing halogenated carboxylic acids presence provides enhanced activities, which can be attributed their low pK values reduces by phenolate protonation well electron‐withdrawing character makes oxo species more electrophilic oxidant. Moreover, best our knowledge, new system accomplish alkylbenzenes highest yields so far reported homogeneous arene hydroxylation catalysts. Overall data provide proof‐of‐concept how Mn(II)/H /RCO systems are easily tunable means solvent, acid additive, and steric demand ligand. chemo‐ site‐selectivity patterns current system, negligible KIE, observation NIH‐shift, effectiveness t BuOOH overall suggest bonds proceeds metal‐based mechanism, no significant involvement hydroxyl radicals, via oxide intermediate. magnified image

Язык: Английский

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Visible-Light-Induced Difluoroalkylation of 1-(Allyloxy)-2-(1-arylvinyl)benzenes and 1-(1-Arylvinyl)-2-(vinyloxy)benzenes: Synthesis of Bis-Difluoroalkylated Benzoxepines and 2H-Chromenes

Organic Letters, Год журнала: 2022, Номер 24(31), С. 5791 - 5796

Опубликована: Авг. 2, 2022

A novel visible-light-mediated difluoroalkylation of 1-(allyloxy)-2-(1-arylvinyl)benzenes and 1-(1-arylvinyl)-2-(vinyloxy)benzenes for the synthesis bis-difluoroalkylated benzoxepines 2H-chromenes is developed. This method features mild reaction conditions, good regioselectivity, a wide substrate scope, functional-group compatibility, late-stage modification. Preliminary mechanistic studies reveal that generation CF2CO2Et radical more prone to with double bond aryl group.

Язык: Английский

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Biomedical engineered nanomaterials to alleviate tumor hypoxia for enhanced photodynamic therapy

Pharmacological Research, Год журнала: 2022, Номер 186, С. 106551 - 106551

Опубликована: Ноя. 9, 2022

Язык: Английский

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Oxepine-Based π-Conjugated Ladder/Step-Ladder Polymers with Excited -State Aromaticity

Macromolecules, Год журнала: 2024, Номер 57(3), С. 991 - 1000

Опубликована: Янв. 24, 2024

Ladder polymers with backbones of uninterrupted ring-fused units have attracted academic and industrial attention for decades because their extended π-conjugation intrinsic microporosity possible potential applications in organic optoelectronics membrane gas separations. We report herein the synthesis characterization a new series oxepine-based ladder/step-ladder prepared by acid-promoted intramolecular aromatic electrophilic cyclization reactions on alkyne-containing poly(arylene ether) precursors. In contrast to more common annulations that produce five- six-membered rings, we seven-membered ring can be regioselectively quantitatively generated postpolymerization. Model compounds repeating also been synthesized, X-ray crystallographic analysis reveals nonplanar contorted structure is present polymers. More interestingly, appear display photoinduced planarization 8 π electron oxepine driven excited-state stabilization energy, as indicated large Stokes shift.

Язык: Английский

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