Development of Pseudo-C₂-symmetric Chiral Binaphthyl Monocarboxylic Acids for Enantioselective C(sp³)–H Functionalization Reactions under Rh(III) Catalysis

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(7), P. 4271 - 4277

Published: March 22, 2021

Enantioselective C(sp3)–H functionalization reactions using high-valent group 9 metal catalysts with cyclopentadienyl ligands have been achieved by the introduction of appropriate chiral carboxylic acids. However, diversity acids, as well that applicable substrate structures remains limited. Herein, we report pseudo-C2-symmetric tunable acids a binaphthyl backbone and their application to enantioselective amidation 2-alkylpyridines related heteroaromatic substrates. The fixed cyclic structure pseudo-C2-symmetry developed would reduce conformational flexibility ambiguity. combination an optimal acid sterically hindered rhodium catalyst (Cp*tBuRhIII) exhibited high enantioselectivity (up 96:4 er).

Language: Английский

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Enantioselective Access to Spirolactams via Nitrenoid Transfer Enabled by Enhanced Noncovalent Interactions

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(17), P. 6363 - 6369

Published: April 22, 2021

Described herein is the Ir-catalyzed enantioselective access to chiral spirolactam products via nitrenoid transfer aromatic ipso-carbons. The key strategy for precise stereocontrol enhance secondary attractive and repulsive interactions between catalyst substrates by introduction of a traceless O-silyl achiral auxiliary, thus effectively differentiating two prochiral faces arenol-derived 1,4,2-dioxazol-5-one substrates.

Language: Английский

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Asymmetric C–H Activation for the Synthesis of P- and Axially Chiral Biaryl Phosphine Oxides by an Achiral Cp*Ir Catalyst with Chiral Carboxylic Amide

ACS Catalysis, Journal Year: 2021, Volume and Issue: 12(1), P. 193 - 199

Published: Dec. 14, 2021

The catalytic synthesis of P- and axially chiral biaryl phosphine oxides was realized via the Cp*Ir-catalyzed asymmetric C–H coupling tertiary substituted with diarylacetylenes. carboxylic amides were used to control stereoselectivity in activation, enabling construction up 96% ee. Transformation products into trivalent ligands has also been demonstrated.

Language: Английский

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Transition Metal-Catalyzed Regioselective Direct C–H Amidation: Interplay between Inner- and Outer-Sphere Pathways for Nitrene Cross-Coupling Reactions

Accounts of Chemical Research, Journal Year: 2022, Volume and Issue: 55(15), P. 2123 - 2137

Published: July 19, 2022

ConspectusCatalytic C–N bond cross-coupling reactions have been a subject of fundamental importance in synthetic organic and medicinal chemistry because amides amines are ubiquitous motifs natural products, functional materials, pharmaceuticals. Since the pioneering works Breslow Mansuy on metalloporphyrin-catalyzed direct hydrocarbon amidation using sulfonyliminoiodinane reagents, substantial development has achieved toward practical selective amination protocols. Notably, Du Bois's group developed dirhodium(II,II) carboxylate catalytic system for C(sp3)–H amidations via Rh-sulfonyl nitrene intermediates. Yet, this protocol suffers from competitive alkene aziridination is limited to electron-rich tertiary ethereal C–H bonds; analogous arenes remained ineffective.This Account discusses our early effort explore cyclopalladated complexes ortho-selective C(aryl)–H amidations. While Buchwald–Hartwig cannot be directly applied arenes, effective 2-arylpyridines occurred when an external oxidant such as K2S2O8 was employed. Preliminary studies suggested that may proceed through reactive Pd-nitrene Aiming develop more diversified protocols, we employed nosyloxycarbamates precursors Pd-catalyzed ortho-amidation N-pivalanilides. Likewise, benzoic acids produce anthranilic acids, which versatile many medicinally valuable heterocycles. In attempt expand C(aryl)–N coupling amines, studied d6 piano-stool Cp*Rh(III) systems [Cp* = pentamethylcyclopentadienyl]. Our work established sound reaction platform based electrophilic aminating reagents including N-chloroamines, hydroxyamides, N-carboxyhydrazides formation aryl–metal complexes.Building upon metal-nitrene platform, moved forward examine γ-lactam synthesis by intramolecular carbonyl insertion. Noted nitrenes prone undergo Curtius-type rearrangement form isocyanate; found π-basic Ru(II) center effectively decomposes dioxazolones afford regioselective γ-C(sp3)–H With chiral diphenylethylenediamines (dpen) ligands bearing electron-withdrawing arylsulfonyl substituents, [(p-cymene)Ru(dpen)] complex catalyzed decomposition γ-lactams formal Enantioselective insertion allylic propargylic bonds also with remarkable tolerance C═C C≡C bonds. selectivity [(p-cymene)Ru] switched give dihydroquinolinones l-proline ligand. Recently, aimed address regiocontrolled unactivated methylene NiH catalyst. benzyl can differentiated their dissociation energies steric properties, groups making up skeleton display similar electronic properties. context, exploited five-membered nickelacycle terminate NiH-mediated chain-walk isomerization, reacted furnish C(sp3)–N at γ-methylene position.This summarizes contribution activation. By exploiting inner-sphere outer-sphere pathways, successfully protocols target The mechanistic underpinning different related affiliated will discussed.

Language: Английский

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Chiral Cp^xRhodium(III)‐Catalyzed Enantioselective Aziridination of Unactivated Terminal Alkenes

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(12)

Published: Jan. 27, 2024

Chiral cyclopentadienyl-rhodium(III) Cp

Language: Английский

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Ruthenium-Catalyzed γ-Selective Intermolecular Amidation of Nonactivated Distal Methylene C–H Bonds of Terminal Alkenes via Olefin Chain-Walking Isomerization

ACS Catalysis, Journal Year: 2025, Volume and Issue: unknown, P. 3980 - 3991

Published: Feb. 20, 2025

Language: Английский

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Chiral CpxRh complexes for C–H functionalization reactions

Science Bulletin, Journal Year: 2020, Volume and Issue: 66(3), P. 210 - 213

Published: Sept. 29, 2020

Language: Английский

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Recent advances in oxidative allylic C–H functionalization via group IX-metal catalysis

Chemical Communications, Journal Year: 2020, Volume and Issue: 56(87), P. 13287 - 13300

Published: Jan. 1, 2020

Allylic substitution, pioneered by the work of Tsuji and Trost, has been an invaluable tool in synthesis complex molecules for decades. An attractive alternative to allylic substitution is direct functionalization C-H bonds unactivated alkenes, thereby avoiding need prefunctionalization. Significant early advances were made using palladium catalysis. However, Pd-catalyzed reactions are generally limited terminal olefins with stabilized nucleophiles. Insights from Li, Cossy, Tanaka demonstrated utility RhCpx catalysts functionalization. Since these initial reports, a number key intermolecular Co-, Rh-, Ir-catalyzed have reported, offering significant complementarity reactions. Herein, we report summary recent via group IX-metal π-allyl complexes. Mechanism-driven development new highlighted, potential future developments discussed.

Language: Английский

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Rhodium(III)‐Catalyzed Asymmetric [4+1] and [5+1] Annulation of Arenes and 1,3‐Enynes: A Distinct Mechanism of Allyl Formation and Allyl Functionalization

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(50), P. 22706 - 22713

Published: Sept. 4, 2020

Abstract We report chiral Rh III cyclopentadienyl‐catalyzed enantioselective synthesis of lactams and isochromenes through oxidative [4+1] [5+1] annulation, respectively, between arenes 1,3‐enynes. The reaction proceeds a C−H activation, alkenyl‐to‐allyl rearrangement, nucleophilic cyclization cascade. mechanisms the annulations were elucidated by combination experimental computational methods. DFT studies indicated that, following activation alkyne insertion, alkenyl intermediate undergoes δ ‐hydrogen elimination allylic via six‐membered ring transition state to produce enallene hydride intermediate. Subsequent insertion allyl rearrangement affords several rhodium(III) intermediates, rare η 4 ene‐allyl species with π‐agostic interaction SN 2 ′‐type external attack nitrogen nucleophile, instead C−N reductive elimination, as stereodetermining step.

Language: Английский

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Biocatalytic, Intermolecular C−H Bond Functionalization for the Synthesis of Enantioenriched Amides

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(47), P. 24864 - 24869

Published: Sept. 17, 2021

Abstract Directed evolution of heme proteins has opened access to new‐to‐nature enzymatic activity that can be harnessed tackle synthetic challenges. Among these, reactions resulting from active site iron‐nitrenoid intermediates present a powerful strategy forge C−N bonds with high site‐ and stereoselectivity. Here we report biocatalytic, intermolecular benzylic C−H amidation reaction operating at mild scalable conditions. With hydroxamate esters as nitrene precursors, feedstock aromatic compounds converted chiral amides excellent enantioselectivity (up >99 % ee ) yields 87 %). Kinetic computational analysis the reveals rate‐determining nitrenoid formation followed by stepwise hydrogen atom transfer‐mediated functionalization.

Language: Английский

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