Surmounting Alkoxide Trap Strategy: N-Heterocyclic Carbene Chromium(0)-Catalyzed C-Alkylation between Alcohols

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(19), P. 12481 - 12493

Published: Sept. 8, 2023

The crucial role of the alkoxide trap problem and impact oxidation state chromium center were demonstrated on catalytic activity due to d-wall issue. Through strategy surmounting trap, a Cr(0) catalyst was presented herein for efficient C-alkylation between alcohols via borrowing hydrogen/hydrogen autotransfer. synthesized bis-(N-heterocyclic carbene)-Cr(0) system shows an performance (40 examples, up 96% yield). Only loading cheap readily available base NaOH is effective enough reaction. Compared with Cr(III)/Cr(II), can well avoid d-p π interaction in key metal-alkoxide intermediate, thus overcoming thermodynamic sink problem. It plausible that Cr(III) systems need be reduced Cr(II) weakening effect enhancing by using reductive strong bases. This should helpful development nonprecious transition metal catalysts.

Language: Английский

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Amine-functionalized bifunctional Co^III-NHC complexes: highly effective phosphine-free catalysts for the α-alkylation of nitriles

Chemical Communications, Journal Year: 2024, Volume and Issue: 60(23), P. 3142 - 3145

Published: Jan. 1, 2024

Newly developed amine functionalized NHC-supported Co

Language: Английский

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Borrowing Hydrogen Mechanism in Amine Alkylation by Single Atom Nickel Catalysts

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(15), P. 11332 - 11342

Published: July 15, 2024

The alkylation of amines with alcohols by borrowing hydrogen (BH) is a versatile synthetic route to various relevant compounds, including drugs and agrochemicals. atom economy this reaction, water as the sole byproduct, entails complex mechanism in which alcohol activation can follow multiple competing pathways. interest single catalysts (SACs) combining advantages homogeneous heterogeneous systems motivated computational study on BH catalyzed nickel SACs. We found that oxidation, charge, spin states system, well geometry support, all have strong influence mechanism. pyrrolic support was most reactive dicationic state nearly degenerate singlet triplet configurations. free energy catalyst hydrogenation H2 strongly correlated its reactivity, thus being useful descriptor. Further, followed an unusual reaction pathway takes delivers H equivalents, metal playing spectator role. This provides insights for further development

Language: Английский

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Bio-waste derived Ag/chitin nanocatalyst induces green and efficient N-alkylation of alcohols with amines via borrowing hydrogen strategy

Chemical Engineering Journal, Journal Year: 2025, Volume and Issue: unknown, P. 160587 - 160587

Published: Feb. 1, 2025

Language: Английский

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Ruthenium‐Catalyzed α‐Alkylation of Arylacetonitriles with Primary Alcohols: N‐heterocyclic Carbene‐Amine's Promotional Influence

ChemistrySelect, Journal Year: 2025, Volume and Issue: 10(7)

Published: Feb. 1, 2025

Abstract Transition‐metal‐catalyzed α‐alkylation of nitriles with alcohols is an environmentally benign reaction, and the development simple efficient catalysts for this transformation a growing area research. In study, we report serial bidentate N ‐heterocyclic carbene (NHC) ruthenium complexes different extra donors alcohols. Through adjusting backbone NHC ligands, catalytic activities these could be controlled. The complex ( Ru3 ) bearing amine donor benzimidazolium exhibited highest activity. A large variety α‐alkylated were obtained in 30%–88% yields, by using 1 mol% amount Cs 2 CO 3 (20 mol%). Detailed control experiments deuterium‐labeling suggested that reaction proceeds via borrowing hydrogen pathway.

Language: Английский

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Selective Monoalkylation or Dialkylation of Indenes with Alcohols by Bis-N-Heterocyclic Carbene Manganese

ACS Catalysis, Journal Year: 2024, Volume and Issue: unknown, P. 18032 - 18044

Published: Nov. 22, 2024

Selective direct alkylation of indenes is important for the synthesis and decoration indene derivatives. In contrast to traditional methods, using unactivated alcohol as reagents via borrowing hydrogen or autotransfer highly attractive. However, nature high-lying lowest unoccupied molecular orbital condensation intermediate raises a big challenge development BH system alcohols. Through tuning stability reactivity metal-hydride species by theoretical prediction, herein, we succeeded in developing non-noble Mn-catalyzed selective monoalkylation dialkylation under mild conditions, producing corresponding versatile alkylated satisfactory yields. A broad scope substrates including primary benzylic, aliphatic, amino, hydroxyl, second alcohols well various are tolerated system. Additionally, this method could be used potential precatalyst complexes bioactive molecules. Mechanistic studies control experiments, kinetic investigations, isotope effect, deuterium labeling density functional theory calculations, reveal proper successful process.

Language: Английский

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Direct N‐Alkylation of Amines with Alcohols Catalyzed by N‐Heterocyclic Carbene Cobalt‐Pincer Catalyst under Mild Conditions

Asian Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 13(3)

Published: Jan. 11, 2024

Abstract Alcohols are widely available and can be derived from renewable resources. Catalytic alcohol amination for N ‐alky amine synthesis using the borrowing hydrogen strategy is an environmentally benign prominent sustainable method, which produces water as sole byproduct. However, expensive noble metals generally employed this transformation, while nonprecious metal‐based catalysts were also known reaction have attracted considerable attention recently. Herein, efficient ‐alkylation of amines with alcohols base‐metal cobalt reported. This catalyzed by N‐heterocyclic carbene cobalt‐pincer catalyst operates simply under mild conditions. Various aniline substrates functional groups including nitrile, ether, thioether alkene could well tolerated. Moreover, experimental studies DFT calculations performed to illustrate mechanism. Our results suggest that proceeds via a autotransfer

Language: Английский

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Recent advances in the catalytic applications of NHC-early abundant metals (Mn, Co, Fe) complexes

Advances in organometallic chemistry, Journal Year: 2024, Volume and Issue: unknown, P. 181 - 270

Published: Jan. 1, 2024

Language: Английский

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Alkoxide Trap in Transition‐Metal‐Catalyzed Dehydrogenative Coupling and Borrowing Hydrogen Reactions

ChemCatChem, Journal Year: 2024, Volume and Issue: 16(20)

Published: July 2, 2024

Abstract Dehydrogenative coupling (DC) and borrowing hydrogen(ation) (BH) reactions are crucial in modern organic synthesis, offering efficient sustainable ways to create valuable compounds. However, they often face a significant challenge: the alkoxide trap. This Concept explores trap DC BH reactions, starting with basic mechanisms role of intermediates. It then examines how leads catalyst deactivation reduced selectivity, influenced by thermodynamic kinetic factors. To address this, we review recent advances design, ligand engineering, optimized reaction conditions, along use in‐situ spectroscopy computational modelling, better understand underlying processes guide rational development. Furthermore, this highlights broad applicability DC, across various substrates, underscoring urgency addressing issue unlock their full synthetic potential.

Language: Английский

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Visible-light-induced N-alkylation of anilines with 4-hydroxybutan-2-one

RSC Advances, Journal Year: 2024, Volume and Issue: 14(20), P. 14452 - 14455

Published: Jan. 1, 2024

The synthesis of amines through N-alkylation is particularly attractive. Herein, a strategy for visible-light-induced anilines with 4-hydroxybutan-2-one was developed in the presence NH4Br, which avoid use metals, bases and ligands. In addition, gram-scale experiments proved that system has potential to be scaled.

Language: Английский

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