Chiral Cyclopentadienyl Ligands: Design, Syntheses, and Applications in Asymmetric Catalysis

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 60(24), P. 13198 - 13224

Published: July 16, 2020

The creation of new chiral ligands capable providing high stereocontrol in metal-catalyzed reactions is crucial modern organic synthesis. production bioactive molecules as single enantiomers increasingly required, and asymmetric catalysis with metal complexes constitutes one the most efficient synthetic strategies to access optically active compounds. Herein we offer a historical overview on development derivatives ubiquitous cyclopentadienyl ligand (CpX ), detail their successful application broad range transformations. Those include functionalization challenging C-H bonds beyond, giving an extensive catalogue valuable molecules. A critical comparison existing families, design, synthesis, complexation different metals also provided. In addition, future research directions are discussed further enhance performance CpX enantioselective catalysis.

Language: Английский

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Transition Metal Catalyzed Enantioselective C(sp²)–H Bond Functionalization

ACS Catalysis, Journal Year: 2020, Volume and Issue: 10(23), P. 13748 - 13793

Published: Nov. 12, 2020

Direct catalytic transformation of C–H bonds to new functionalities has provided a powerful strategy synthesize complex molecular scaffolds in straightforward way. Unstinting efforts the synthetic community have helped overcome long-standing major challenge regioselectivity by introducing directing group concept. However, full potential cannot be realized unless activated are stereochemically controlled. The enantioselective bond functionalization could provide an imperative tool for sustainable way synthesizing chiral scaffolds. Despite intrinsic challenges achieving stereocontrol, developed different tools order achieve stereoselective functionalization. In this review, we discuss remarkable recent advances emerging area C(sp2)–H highlight and opportunities, emphasizing techniques so far.

Language: Английский

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Oxygen‐Linked Cyclopentadienyl Rhodium(III) Complexes‐Catalyzed Asymmetric C−H Arylation of Benzo[h]quinolines with 1‐Diazonaphthoquinones

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(28), P. 15510 - 15516

Published: April 16, 2021

Abstract Chiral cyclopentadienyl rhodium (CpRh) complex‐catalyzed asymmetric C−H functionalization reactions have witnessed a significant progress in organic synthesis. In sharp contrast, the reported chiral Cp ligands are limited to C‐linked and often synthetically challenging. To address these issues, we developed novel class of tunable bearing oxygen linkers, which were efficient catalysts for arylation benzo[ h ]quinolines with 1‐diazonaphthoquinones, affording axially heterobiaryls excellent yields enantioselectivity (up 99 % yield, 98.5:1.5 er). Mechanistic studies suggest that reaction is likely proceed by electrophilic activation, followed coupling cyclometalated rhodium(III) complex 1‐diazonaphthoquinones.

Language: Английский

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Transition-metal-catalyzed C–H bond alkylation using olefins: recent advances and mechanistic aspects

Chemical Society Reviews, Journal Year: 2022, Volume and Issue: 51(17), P. 7358 - 7426

Published: Jan. 1, 2022

Transition metal catalysis has contributed immensely to C-C bond formation reactions over the last few decades, and alkylation is no exception. The superiority of such methodologies traditional evident from minimal reaction steps, shorter times, atom economy while also allowing control regio- stereo-selectivity. In particular, hydrocarbonation alkenes grabbed increased attention due its fundamental ability effectively selectively synthesise a wide range industrially pharmaceutically relevant moieties. This review attempts provide scientific viewpoint systematic analysis recent developments in transition-metal-catalyzed various C-H bonds using simple activated olefins. key features mechanistic studies involved these transformations are described briefly.

Language: Английский

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Enantioselective [3+2] Annulation of Aldimines with Alkynes by Scandium‐Catalyzed C−H Activation

Angewandte Chemie International Edition, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 3, 2025

Abstract The enantioselective [3+2] annulation of readily accessible aldimines with alkynes via C−H activation is, in principle, a straightforward and atom‐efficient route for synthesizing chiral 1‐aminoindenes, which are important components wide array natural products, bioactive molecules, functional materials. However, such asymmetric transformation has remained undeveloped to date due the lack suitable catalysts. Here, we report first time using half‐sandwich scandium This protocol enabled synthesis diverse multi‐substituted 1‐aminoindene derivatives 100 % atom‐efficiency, broad substrate scope, high regio‐ enantioselectivity. Density theory (DFT) analyses have revealed that noncovalent C−H⋅⋅⋅π interaction between tert ‐Bu substituent cyclopentadienyl (Cp) ligand phenyl ring an aromatic aldimine played role achieving level work not only offers efficient selective new family but also unprecedented insights into enantioselectivity control Cp‐ligated metal

Language: Английский

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Theoretical Insights into Rare-Earth-Catalyst-Controlled Diastereo- and Enantioselective [3 + 2] Annulation of Aromatic Aldimines with Styrenes

Inorganic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 5, 2025

Rare-earth-catalyzed annulation reactions using alkenes via C–H activation offer an atom-efficient approach to constructing cyclic compounds. However, the mechanisms underlying these remain poorly understood, limiting rational design of related catalytic systems. Recently, Hou and Cong reported unprecedented example rare-earth-catalyst-controlled diastereodivergent asymmetric [3 + 2] aromatic aldimines with alkenes. To elucidate origins diastereo- enantioselectivity, density functional theory calculations were performed. The results revealed that styrene insertion step determines stereoselectivity. Styrene follows a similar metal–styrene interaction pattern across different catalysts. Specifically, during cis-insertion, interacts strongly metal center, exhibiting significant Sc···Ph interactions, whereas such interactions are absent trans-insertion. Thus, when catalyst is employed small ligand, stereoselectivity primarily governed by electronic factors, favoring cis-insertion mode. In contrast, for more sterically hindered catalyst, in insufficient overcome steric effects, leading preference trans-insertion mode, which minimizes hindrance. These findings deeper insights into catalyst-controlled enantioselectivity will also contribute stereospecific rare-earth catalysis.

Language: Английский

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Enantioselective C–H Alkenylation of Ferrocenes with Alkynes by Half-Sandwich Scandium Catalyst

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(6), P. 2470 - 2476

Published: Feb. 2, 2021

The enantioselective C–H alkenylation of ferrocenes with alkynes is, in principle, a straightforward and atom-efficient route for the construction planar-chiral ferrocene scaffolds bearing alkene functionality but has remained scarcely explored to date. Here we report first time highly quinoline- pyridine-substituted by half-sandwich scandium catalyst. This protocol features broad substrate scope, high enantioselectivity, 100% atom efficiency, selectively affording new family N/alkene functionalities. mechanistic details have been clarified DFT analyses. use quinoline/alkene-functionalized product as chiral ligand asymmetric catalysis is also demonstrated.

Language: Английский

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Cp*Co(III)-Catalyzed Enantioselective Hydroarylation of Unactivated Terminal Alkenes via C–H Activation

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(45), P. 19112 - 19120

Published: Nov. 8, 2021

Enantioselective hydroarylation of unactivated terminal akenes constitutes a prominent challenge in organic chemistry. Herein, we reported Cp*Co(III)-catalyzed asymmetric aliphatic alkenes assisted by new type tailor-made amino acid ligands. Critical to the chiral induction was engaging novel noncovalent interaction (NCI), which has seldomly been disclosed C-H activation area, arising from molecular recognition among organocobalt(III) intermediate, coordinated alkene, and well-designed ligand. A broad range C2-alkylated indoles were obtained high yields excellent enantioselectivities. DFT calculations revealed reaction mechanism elucidated origins stereodetermining alkene insertion step.

Language: Английский

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Strong and Confined Acids Catalyze Asymmetric Intramolecular Hydroarylations of Unactivated Olefins with Indoles

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(2), P. 675 - 680

Published: Jan. 5, 2021

In recent years, several organocatalytic asymmetric hydroarylations of activated, electron-poor olefins with electron-rich arenes have been described. contrast, only a few approaches that can handle unactivated, electronically neutral reported and invariably require transition metal catalysts. Here we show how an efficient highly enantioselective catalytic intramolecular hydroarylation aliphatic aromatic indoles be realized using strong confined IDPi Brønsted acid This unprecedented transformation is enabled by tertiary carbocation formation establishes quaternary stereogenic centers in excellent enantioselectivity broad substrate scope includes iodide, azide, alkyl boronate, which further elaborated into bioactive molecules.

Language: Английский

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Modular Access to Spiro-dihydroquinolines via Scandium-Catalyzed Dearomative Annulation of Quinolines with Alkynes

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(48), P. 20462 - 20471

Published: Nov. 23, 2021

The catalytic enantioselective construction of three-dimensional molecular architectures from planar aromatics such as quinolines is great interest and importance the viewpoint both organic synthesis drug discovery, but there still exist many challenges. Here, we report scandium-catalyzed asymmetric dearomative spiro-annulation with alkynes. This protocol offers an efficient selective route for spiro-dihydroquinoline derivatives containing a quaternary carbon stereocenter unprotected N–H group readily accessible diverse alkynes, featuring high yields, enantioselectivity, 100% atom-efficiency, broad substrate scope. Experimental density functional theory studies revealed that reaction proceeded through C–H activation 2-aryl substituent in quinoline by scandium alkyl (or amido) species followed alkyne insertion into Sc–aryl bond subsequent 1,2-addition resulting alkenyl to C═N unit moiety. work opens new avenue dearomatization quinolines, leading spiro were previously difficult access other means.

Language: Английский

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