Noninnocent Azo-Aromatic Cobalt(II)-Catalyzed sp³ C–H Alkylation of Fluorenes with Alcohols

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(3), P. 1910 - 1926

Published: Jan. 11, 2024

Herein, employing well-defined redox noninnocent cobalt(II) complexes an efficient sp3 C–H alkylation of fluorenes using alcohols as alkylating agents to result in alkylated is reported. The catalytic protocol was versatile with various and benzyl alcohols. It also showed very good functional group tolerance both fluorenes. Moreover, single-step simultaneous di C–C well the C–N reaction observed this protocol. Such selective dialkylation indeed beneficial. Several control experiments, deuterium labeling, 1H NMR kinetic studies have revealed a ligand radical-based borrowing hydrogen mechanism involving azo-aromatic cobalt catalysts for

Language: Английский

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A Phosphine-Oxide Cobalt(II) Complex and Its Catalytic Activity Studies toward Alcohol Dehydrogenation Triggered Direct Synthesis of Imines and Quinolines

Inorganic Chemistry, Journal Year: 2024, Volume and Issue: 63(21), P. 9786 - 9800

Published: May 13, 2024

Herein, a new pincer-like amino phosphine donor ligand, H2L1, and its phosphine-oxide analog, H2L2, were synthesized. Subsequently, cobalt(II) complexes 1 2 synthesized by the reaction of anhydrous Co(II)Cl2 with ligands H2L1 respectively. The fully characterized various physicochemical spectroscopic characterization techniques. Finally, identity was confirmed single crystal X-ray structure determination. ligand containing complex converted to oxide in air acetonitrile solution. Both investigated as precatalysts for alcohol dehydrogenation-triggered synthesis imines air. more efficient than 1. A wide array alcohols amines successfully reacted mild condition result good excellent yields. Precatalyst also highly varieties quinolines As H2L2 has side arms that can be deprotonated, we base (KOtBu) promoted deprotonation events studies DFT calculations. These have shown mono amine arm attached pyridine is quite feasible, leads dearomatized pyridyl ring 2a. mechanistic investigations catalytic reaction, combination experimental computational studies, suggested complex, 2a acted an active catalyst. proceeded through hydride transfer pathway. activation barrier this step calculated 26.5 kcal/mol, which consistent temperature under aerobic conditions. Although are explored such reactions, ligand-containing still unexplored.

Language: Английский

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Dinuclear Ru(II) Schiff Base Complex Catalyzed One-Pot Synthesis of Quinolines through Acceptorless Dehydrogenative Coupling of Secondary Alcohols with 2-Nitrobenzyl Alcohol

Organometallics, Journal Year: 2024, Volume and Issue: 43(10), P. 1190 - 1202

Published: May 10, 2024

Dinuclear Ru(II) complexes [(p-cymene)2(RuCl)2L1]2X (X = BF4 (Ru1); X PF6 (Ru2)) and mononuclear [(p-cymene)(RuCl)L2]BF4 (Ru3) (where L1 N,N′-(3,3′,5,5′-tetraisopropyl-[1,1′-biphenyl]-4,4′-diyl)bis(1-(pyridin-2-yl)methanimine); L2 N-(2,6-diisopropyl-phenyl)-1-(pyridin-2-yl)-methanimine) have been synthesized characterized by spectroscopic analytical techniques. Ru1 Ru2 orchestrate direct transformation of 2-nitrobenzyl alcohols to quinolines under mild conditions with significant efficiency even when employed at a minimal catalyst loading 0.1 mol %. Proportional experiments carried out the corresponding complex Ru3 keeping Ru content same (0.2 % Ru3) reveal superior activity bimetallic system for one-pot quinoline synthesis. Late-stage functionalization bioactive steroids scale-up synthesis demonstrate practical applicability present system. A probable mechanism this conversion is proposed based on trapping many intermediates ESI-mass spectroscopy. These mechanistic studies further substantiated ReactIR monitoring progress reaction in real time.

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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Molybdenum Catalyzed Acceptorless Dehydrogenation of Alcohols for the Synthesis of Quinolines

ChemCatChem, Journal Year: 2024, Volume and Issue: 16(15)

Published: Feb. 23, 2024

Abstract The first molybdenum triazolylidene complexes catalyzing the atom‐economical synthesis of quinolines through acceptorless dehydrogenative coupling alcohols is reported. A new family Mo(0) bearing chelating bis‐1,2,3‐triazolylidene, pyridyl‐1,2,3‐triazolylidene, and bis‐triazole ligands have been prepared applied as catalysts for quinolines. Interestingly, Mo bis‐1,2,3‐triazolylidene with alkyl groups (Et, n ‐Bu) displayed superior catalytic activities than those containing aryl substituents on rings. Control experiments corroborated that reaction involves dehydrogenation pathway.

Language: Английский

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Ligand Redox Controlled Amine Dehydrogenation and Imine Hemilability in Singlet Diradical Azo-aromatic Ni(II) Complexes: Characterization of the Electron Transfer Series of Azo-imine Complexes of Ni(II)

Dalton Transactions, Journal Year: 2024, Volume and Issue: 53(24), P. 10250 - 10260

Published: Jan. 1, 2024

Singlet diradical Ni( ii ) complexes [1] and [2] of azo-amine azo-imine ligands have shown ligand redox-induced amine dehydrogenation imine hemilability, respectively.

Language: Английский

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A well-defined phosphine free metal-ligand cooperative route for N-alkylation of aromatic amines via activation of renewable alcohols catalyzed by a NNN pincer cobalt(II) complexes

Dalton Transactions, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Two cobalt( ii ) complexes C1 and C2, supported by an NNN pincer, were synthesized, characterized with various techniques. These utilized to study catalytic activity in the N -alkylation of amines via borrowing hydrogen strategy.

Language: Английский

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An o-Phenylene Bridged Noninnocent Bis-Azopyridyl Ligand and Its Copper Complexes: Synthesis, Characterization of Electron Transfer Events, and Use of the Cu Complexes for Oxidation of Alcohols

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

Published: April 14, 2025

In this report, an o-phenylene-bridged tetradented redox-noninnocent bis-azopyridyl ligand [L] and its copper complexes [1] [2] were synthesized characterized. The electron transfer events of [L], as well [2], characterized by single-crystal X-ray structure determination, various spectroscopic studies, DFT calculations. While [[L]Cu(II)Cl2] has unreduced [[L]•-Cu(I)Cl] contains a one-electron-reduced [L]•- , which is antiferromagnetically coupled with the unpaired spin on Cu(II). Reduction one generated complex [2]•-, remained in electronically bistable situation form valence tautomers: [2A]•-, [[L]•-Cu(I)Cl]•- [2B]•-, [[L]2-Cu(II)Cl]•-. Further one-electron reduction [2]•- mixture Cu complexes: [2A]-, [[L]2-Cu(I)]- [2B]-, [[L]3•-Cu(II)]-. Complexes examined for catalytic oxidation alcohols. was more efficient than [1]. protocol highly versatile both primary secondary aromatic aliphatic Mechanistic investigations showed that [[L]•-Cu(I)OCH2Ph]•- (A) active catalyst, subsequently, through ligand-based redox events, acted catalyst over course reaction.

Language: Английский

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Aerial Oxidation of Alcohols by an Amide and Imidazole Functionalized Bioinspired Cu‐Complex and Its Switching with N‐Oxides

ChemistrySelect, Journal Year: 2025, Volume and Issue: 10(18)

Published: May 1, 2025

Abstract In this work, employing an imidazole and amide functionalized pincer like Cu(II) complex as a pre‐catalyst, alcohol oxidation reaction without N‐oxide is explored. This was very active for the of benzyl alcohol. The best catalytic activity observed with 1 mmol alcohol, 4 mol% 20 KO t Bu in toluene at 70 °C 24 h. Both primary well secondary alcohols were successfully oxidized. It found that, protocol more efficient (5–12 h time) than (∼24 h). by can be switched N‐oxides 2,2,6,6‐tetramethylpiperidinyloxy (TEMPOH) 9‐azabicyclo[3.3.1]nonane N ‐Oxyl (ABNOH). mechanism studied UV–vis, EPR X‐ray photoelectron spectral studies. Thus, versatile showed good functional group tolerance substitutions on aromatic alcohols. Aerial oxygen acted sole oxidant cooperation / Cu(I) redox events. exhibited switchable behavior presence N‐oxide. Though Cu‐complex catalyzed explored, such where occurs containing inert ligand cocatalyst scarce.

Language: Английский

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Quinoline schiff bases (QSBs) and their derivatives: emerging trends in antimicrobial agents

Journal of Coordination Chemistry, Journal Year: 2025, Volume and Issue: unknown, P. 1 - 34

Published: May 20, 2025

Language: Английский

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