NiH-Catalyzed Regio- and Enantioselective Hydroalkylation for the Synthesis of β- or γ-Branched Chiral Aromatic N-Heterocycles

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(40), С. 22122 - 22134

Опубликована: Сен. 25, 2023

A nickel hydride-catalyzed regio- and enantioselective hydroalkylation reaction was developed to give access a library of chiral β- or γ-branched aromatic N-heterocycles. This intriguing asymmetric transformation features excellent selectivities, step- atom-economies, generating two kinds products through one synthetic strategy. Furthermore, the possible mechanism extensively investigated using numerous control experiments density functional theory calculations.

Язык: Английский

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C-H alkylation of pyridines with olefins catalyzed by imidazolin-2-iminato-ligated rare-earth alkyl complexes

Science China Chemistry, Год журнала: 2023, Номер 66(6), С. 1804 - 1813

Опубликована: Май 10, 2023

Язык: Английский

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Bifunctional NHC-Promoted C2-Alkylation of Pyridine via Ni–Al Bimetallic-Catalyzed Hydroarylation of Unactivated Alkenes

ACS Catalysis, Год журнала: 2023, Номер 13(9), С. 6068 - 6075

Опубликована: Апрель 18, 2023

Achieving site-selective alkylation with pyridine under transition metal catalysis has remained a long-standing challenge, especially when using unactivated alkene as an alkylating reagent. We herein describe C2-alkylation of Ni–Al bimetallic and directing bifunctional N-heterocyclic carbene (NHC) ligand through hydroarylation alkenes. A broad range C2-alkylated pyridines various functionalities could be prepared in high efficiency (up to 99% yield) C2-selectivity, the scope heterocycles is not limited but can expanded other azines like pyrazines pyrimidines. Mechanistic studies suggest that NHC–Ni–Al–pyridine complex responsible for site selectivity control reductive elimination might rate-determining step.

Язык: Английский

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Nickel(II)/BINOL-catalyzed enantioselective C–H activation via desymmetrization and kinetic resolution

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Авг. 20, 2024

The field of nickel catalysis has witnessed remarkable growth in recent years. However, the use catalysts enantioselective C-H activation remains a daunting challenge because their variable oxidation states, intricate coordination chemistry, and unpredictable reactivity patterns. Herein, we report an reaction catalyzed by commercially available air-stable nickel(II) catalyst. Readily simple (S)-BINOL is used as chiral ligand. This operationally protocol enables synthesis planar metallocenes high yields with excellent enantioselectivity through desymmetrization kinetic resolution. Air-stable nickelacycle intermediates are first synthesized via nickelation shown to be possible reaction. Deuterium-labeling studies, alongside characterization transformation species, suggest that cleavage enantio-determining step. Moreover, large-scale diverse synthetic transformations underscore practicality this protocol.

Язык: Английский

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Site‐Selective C−H Alkenylation of N‐Heteroarenes by Ligand‐Directed Co/Al and Co/Mg Cooperative Catalysis**

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(17)

Опубликована: Март 1, 2023

Abstract We report herein the design and development of Co/Al Co/Mg bimetallic catalysts, supported by a phosphine/secondary phosphine oxide (PSPO) bifunctional ligand, for site‐selective C−H alkenylation nitrogen‐containing heteroarenes with alkynes. These catalysts enable pyridine, pyridone, imidazo[1,2‐ ]pyridine derivatives at site proximal to Lewis basic nitrogen or oxygen atom, which represents selectivity profile distinct from that previously developed cobalt‐diphosphine/aluminum catalyst. The alkenylated products were obtained in moderate good yields using various heterocycles differently substituted internal Kinetic isotope effect experiments suggest irreversibility activation step, relevance rate‐limiting step depends on reaction conditions. Density functional theory calculations indicate ligand‐to‐ligand hydrogen transfer is common mechanism activation.

Язык: Английский

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C–H Functionalization of Arenes via NHC-Supported Ni/Al Bimetallic Catalysis

Synthesis, Год журнала: 2023, Номер 55(24), С. 4049 - 4061

Опубликована: Июнь 21, 2023

Abstract Despite the C–H functionalization of arenes offering an efficient synthetic route towards functionalized aromatic compounds with high atom- and step-economy, low reactivity bond makes this transformation rather challenging. Compared mono-metal catalysis, introduction bimetallic catalysis would greatly enhance selectivity transformation. In review, we highlight recent progress in via NHC-Ni/Al catalysis. The added aluminum as a co-catalyst activate arene through Lewis acid-base interaction, regioselectivity could be controlled synergism NHC-Ni Al. This strategy also applied enantioselective alkylation well-designed chiral NHC ligands. 1 Introduction 2 Addition to Alkynes Activation 3 Alkylation Ni/Al Bimetallic Catalysis 3.1 Racemic Hydroarylation Alkenes 3.2 Asymmetric 4 Conclusion Outlook

Язык: Английский

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Copper‐Catalyzed Asymmetric Acylboration of 1,3‐Butadienylboronate with Acyl Fluorides

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(43)

Опубликована: Сен. 15, 2023

Abstract We report herein a Cu‐catalyzed regio‐, diastereo‐ and enantioselective acylboration of 1,3‐butadienylboronate with acyl fluorides. Under the developed conditions, reactions provide ( Z )‐β,γ‐unsaturated ketones bearing an α‐tertiary stereocenter high ‐selectivity excellent enantioselectivities. While direct access to highly enantioenriched E ‐isomers was not successful, we showed that such molecules can be synthesized optical purities via Pd‐catalyzed alkene isomerization from corresponding ‐isomers. The orthogonal chemical reactivities functional groups embedded in ketone products allow for diverse chemoselective transformations, which provides valuable platform further derivatization.

Язык: Английский

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Nickel-catalyzed direct stereoselective α-allylation of ketones with non-conjugated dienes

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

Опубликована: Ноя. 22, 2023

The development of efficient and sustainable methods for the construction carbon-carbon bonds with simultaneous stereoselective generation vicinal stereogenic centers is a longstanding goal in organic chemistry. Low-valent nickel(0) complexes which promote α-functionalization carbonyls leveraging its pro-nucleophilic character conjunction suitable olefin acceptors are scarce. We report Ni(0)NHC catalyst selectively converts ketones non-conjugated dienes to synthetically highly valuable α-allylated products. directly activates α-hydrogen atom carbonyl substrate transferring it acceptor. transformation creates adjacent quaternary tertiary diastereoselective enantioselective manner. Computational studies indicate ability trigger ligand-to-ligand hydrogen transfer process from ketone substrate, setting selectivity process. shown selective functionalization α-C-H bond groups by opens up new opportunities exploit 3d-metal catalysis access chiral building blocks.

Язык: Английский

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Pd–NHC (NHC = N-Heterocyclic Carbene)-Catalyzed B-Alkyl Suzuki Cross-Coupling of 2-Pyridyl Ammonium Salts by N–C Activation: Application to the Discovery of Agrochemical Molecular Hybrids

Organic Letters, Год журнала: 2024, Номер 26(11), С. 2309 - 2314

Опубликована: Март 11, 2024

2-Alkylpyridines are a privileged scaffold throughout the realm of organic synthesis and play key role in natural products, pharmaceuticals, agrochemicals. Herein, we report first B-alkyl Suzuki cross-coupling 2-pyridyl ammonium salts to access functionalized 2-alkylpyridines. The use well-defined, operationally simple Pd-NHCs permits for an exceptionally broad scope challenging C–N with organoboranes containing β-hydrogen, representing novel method discovery highly sought-after molecules plant protection.

Язык: Английский

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Nickel(II)/Salox-Catalyzed Enantioselective C–H Functionalization

ACS Central Science, Год журнала: 2025, Номер 11(1), С. 127 - 135

Опубликована: Янв. 2, 2025

Recently, nickel catalysts have garnered considerable attention for their efficacy and versatility in asymmetric catalysis, attributed to distinctive properties. However, the use of cost-effective sustainable divalent C–H activation/asymmetric alkene insertion poses significant challenges due intricate control stereochemistry transformation tetracoordinate C–Ni(II) intermediate. Herein, we report a Ni(II)-catalyzed enantioselective C–H/N–H annulation with oxabicyclic alkenes. This protocol offers straightforward access chiral [2,2,1]-bridged bicyclic compounds bearing four consecutive stereocenters high enantioselectivity (up 96% ee). The development sterically hindered salicyloxazoline (Salox) ligand, TMS-Salox, is key success this protocol. Mechanistic investigations unveiled that Ni(III)-metalacyclic intermediate was formed through situ oxidation achiral organometallic Ni(II) species coordination Salox ligand. process led creation tailored pocket guides approach alkenes, thereby influencing determining stereochemistry.

Язык: Английский

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