Recent advances on cross-coupling of alcohols via borrowing hydrogen catalysis

Chemical Communications, Journal Year: 2024, Volume and Issue: 60(30), P. 4002 - 4014

Published: Jan. 1, 2024

This article highlights the recent advances and significance of β-alkylation reactions towards synthesis higher order alcohols.

Language: Английский

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Highly Efficient Base Catalyzed N‐alkylation of Amines with Alcohols and β‐Alkylation of Secondary Alcohols with Primary Alcohols

ChemCatChem, Journal Year: 2023, Volume and Issue: 15(20)

Published: Aug. 8, 2023

Abstract Borrowing hydrogen (BH) reactions are very useful for the sustainable synthesis of C−C and C−N bonds. They generally operate with transition metal‐based catalysts along stoichiometric/catalytic amounts added base. Here we report that two catalytic transformations, carried out BH methodology, i. e. N ‐alkylation amines alcohols β‐alkylation secondary primary alcohols, can be performed effectively just base under air without using any catalyst. The mechanism is proposed to based on oxidation alcohol aldehyde followed by condensation an unsaturated intermediate which undergoes transfer hydrogenation product.

Language: Английский

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Recent Advances in the Use of 2‐Aminobenzyl Alcohols in the Synthesis of Quinolines, Quinazolines and Other N‐Heterocycles

Advanced Synthesis & Catalysis, Journal Year: 2024, Volume and Issue: 366(10), P. 2142 - 2164

Published: Jan. 17, 2024

Abstract N‐Heterocyclic compounds, in particular, quinolines and quinazolines are frequently used medicinal chemistry. Therefore, the direct clean synthesis of these valuable scaffolds has been a great interest for many years. 2‐Aminobenzyl alcohols as an alternative reactant instead unstable expensive 2‐aminobenzaldehydes can be construction N‐fused heterocycles including quinolines, quinazolines, oxazines, thiazines, selenazines, imidazoles, diazepines, etc. In this review article, we have discussed recent developments use 2‐aminobenzyl diverse heterocycles.

Language: Английский

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Ruthenium-catalyzed β-alkylation of secondary alcohols with primary alcohols: Protic N-heterocyclic carbene's promotional influence

Journal of Molecular Structure, Journal Year: 2024, Volume and Issue: 1305, P. 137815 - 137815

Published: Feb. 17, 2024

Language: Английский

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Heteroditopic Chelating NHC Ligand-Supported Co^III Complexes: Catalysts for the Reductive Functionalization of Carbon Dioxide under Ambient Conditions

Organometallics, Journal Year: 2023, Volume and Issue: 42(12), P. 1395 - 1403

Published: April 17, 2023

Synthesis and characterization of heteroditopic chelating NHC ligand-supported air stable CoIII–NHC complexes (1a–d), featuring variable triazole N-substituents thus, being structurally tunable, are reported. These were observed to be very effective catalysts for the reductive functionalization CO2 with aromatic amines using hydrosilane under ambient conditions (1 bar pressure room temperature) yield diverse N-formylated amines, importantly, catalytic activity was found reasonably tuned by N-substituents, which is probably due some electronic modulations, supported electrochemical analysis, rather than any considerable steric alterations as indicated percent buried volume calculation. Notably, corresponding generated in situ also equally effective. It worth mentioning that this first report on N-formylation less nucleophilic primary employing a homogeneous Co complex, best our knowledge. In addition, control experiments suggest protocol proceeds via hydride formoxysilane intermediate formation.

Language: Английский

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N-Heterocyclic Carbene-Supported Nickel-Catalyzed Selective (Un)Symmetrical N-Alkylation of Aromatic Diamines with Alcohols

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 88(2), P. 1135 - 1146

Published: Jan. 5, 2023

The "borrowing hydrogen" (BH) approach for the N-alkylation of phenylenediamines using alcohols as coupling partners is highly challenging due to selectivity issue generated products. Furthermore, development base-metal systems that can potentially substitute precious metals with competitive activity a major challenge in BH catalysis. We present herein an efficient protocol N,N'-di-alkylation aromatic diamines situ-generated Ni-NHC complex from NiCl2 and ligand L1, which gave access wide range N,N'-di-alkylated orthophenylene (rather than generally observed benzimidazole derivatives), meta- para-phenylene along 2,6-diamino pyridine derivatives good excellent yields. Moreover, catalyst system was also successful derivatization clinically important drug molecule, Dapsone. Notably, could be applied effectively synthesize unsymmetrically substituted via sequential alkylation first report best our knowledge. Diverse control experiments including deuterium incorporation studies suggest proceeds sequence.

Language: Английский

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β‐Alkylation through Dehydrogenative Coupling of Primary Alcohols and Secondary Alcohols Catalyzed by Thioether‐Functionalized N‐Heterocyclic Carbene Ruthenium Complexes

European Journal of Inorganic Chemistry, Journal Year: 2023, Volume and Issue: 26(23)

Published: May 24, 2023

Abstract A catalytic system for the direct β‐alkylation of secondary alcohol with primary has been investigated. In this work, a series cationic Ru(II)(η 6 ‐ p ‐cymene) complexes thioether‐functionalized N‐heterocyclic carbene ligands (imidazole‐based 1 – l and benzimidazole‐based 2 e ) have successfully synthesized evaluated as catalysts. This investigation shows that modifications in ligand moiety (thioether group and/or NHC core) strong effect on both selectivity reactivity. Imidazole‐based complex c , only mol % catalyst loading, displayed best activity well highest β‐alcohol up to 98 : tandem borrowing hydrogen/aldol methodology. Applied wide range substrates, β‐alkylated alcohols obtained moderate yields, but generally complete conversion very high selectivity.

Language: Английский

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Mechanistic Insights into a Co(II)-Coordinated “Free” Metal Site of 2D Zinc-Based MOFs for β-Alkylation of Secondary Alcohols with Primary Alcohols

Inorganic Chemistry, Journal Year: 2023, Volume and Issue: 62(45), P. 18689 - 18696

Published: Oct. 28, 2023

Through in-depth study of the properties and reaction mechanisms catalysts, it is possible to better optimize catalytic systems improve efficiency selectivity. This remains one challenges in field catalysis. Therefore, research design catalysts play crucial roles understanding optimizing mechanisms. A robust 2D zinc-based MOFs (Zn-HA) supported Co(II) ion catalyst (Zn-HA@Co) has been designed synthesized via a coordination-assisted strategy for β-alkylation secondary alcohols with primary alcohols. The characterization demonstrated that anchoring on Zn-HA coordination could efficiently enhance dispersity interaction between MOFs. Importantly, density functional theory results have provided mechanistic insights into energy HOMO LUMO Zn-HA@Co as well change entire process after interacting reactants specific changes each orbital. effectively lower barrier process. We expect our will serve valuable guideline

Language: Английский

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Bimetallic Ru(II) Complex Catalysed β‐Alkylation of Secondary Alcohols and α‐Alkylation of Ketones: Selective Formation of Saturated Ketones

European Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 27(24)

Published: March 29, 2024

Abstract Ru(II) bimetallic [( p ‐cymene) 2 (RuCl) L 1 ]2X (X=BF 4 ( Cat2 ); X=PF 6 Cat3 )) and monometallic ‐cymene)(RuCl)L ]BF Cat4 ) (where =N,N’‐(3,3’,5,5’‐tetraisopropyl‐[1,1’‐biphenyl]‐4,4’‐diyl)bis(1‐(pyridin‐2‐yl)methanimine); =N‐(2,6‐diisopropyl‐phenyl)‐1‐(pyridin‐2‐yl)‐methanimine) catalyse selective synthesis of saturated ketones using β‐alkylation secondary alcohol or α‐alkylation with primary alcohol. Notably, a single catalyst facilitates the oxidation both alcohols followed by condensation hydrogenation yielding α‐alkylated ketones. Remarkably, this system allows loading as low 0.01 mol% for 0.005 ketone, delivering access to wide array derivatives yields ~97 %. Complex , in particular, orchestrates one‐pot alkylation reactions high turnover frequency (TOF) 5.6 10 5 h −1 0.0001 mol%. A comparative study between complexes reveals that complex exhibits better selectivity formation presumably owing cooperative effect metal centres. The scale‐up highlights practical applicability catalytic approach. To delve into plausible mechanisms, we conducted initial investigations through meticulously controlled experiments spectroscopic analysis.

Language: Английский

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Heteroditopic NHC Ligand Supported Manganese(I) Complexes: Synthesis, Characterization, and Activity as Non‐bifunctional Phosphine‐Free Catalyst for the α‐Alkylation of Nitriles

Chemistry - A European Journal, Journal Year: 2023, Volume and Issue: 30(1)

Published: Oct. 9, 2023

Abstract In the present work, several manganese(I) complexes of chelating heteroditopic ligands Mn1–3 , featuring ImNHC (imidazol‐2‐ylidene) connected to a 1,2,3‐triazole‐N or tzNHC (1,2,3‐triazol‐5‐ylidene) donors via methylene spacer, with possible modifications at triazole backbone have been synthesized and completely characterized. Notably, CO stretching frequencies, electrochemical analysis, frontier orbital analysis certainly suggest that ImNHC‐tzNHC stronger donation capabilities than related ImNHC‐Ntz ligand in complexes. Moreover, these well‐defined phosphine‐free Mn(I)−NHC found be effective non‐bifunctional catalysts for α‐alkylation nitriles using alcohols importantly, catalyst Mn1 containing weaker triazole‐N donor displayed higher activity compared Mn2 / Mn3 an unsymmetrical bis‐carbene (ImNHC tzNHC). A wide range aryl were coupled diverse (hetero)aromatic as well aliphatic get corresponding products good excellent yields (32 examples, up 95 % yield). The detailed mechanistic studies including deuterium labelling experiments reveal reaction follows Borrowing Hydrogen pathway.

Language: Английский

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