NNN Pincer-Manganese-Catalyzed Guerbet-Type β-Alkylation of Alcohols under Microwave Irradiation

Organometallics, Journal Year: 2023, Volume and Issue: 42(14), P. 1818 - 1831

Published: June 24, 2023

A series of manganese carbonyl complexes based on bis(imino)pyridine ligands the type R2NNN (R = Cy, iPr, Ph, p-FC6H4) were synthesized. While complex appears to be an NN bidentate-Mn(I) triscarbonyl species in solid state, solution, there is a gradual loss carbon monoxide leading first NNN pincer-Mn(I) biscarbonyl complex, which finally disproportionates pincer-Mn(II) dibromide and pincer-Mn(0) complex. Evidence for this transformation has been obtained from single-crystal X-ray diffraction, IR, EPR, HRMS analysis. The apparently faster with cyclohexyl-substituted than others. considered (0.05 mol %) utilized catalyzing β-alkylation secondary alcohols at 140 °C air under conventional heating (12 h), as well microwave (2 h) presence 2.5 % NaOtBu. Among complexes, catalyst (p-FC6H4NNN)Mn(CO)2Br was found highly efficient. heating, maximum 92% (1840 TON 153 TOs/h) β-alkylated product obtained; provided 85% yield (1700 850 just 2 h. catalytic system successfully implemented alkylate several other alcohols, (35 examples). analyses indicate intermediates cycle both pincer-Mn(II)/Mn(0) couple. Deuterium labeling studies point involvement C–H bond activation rate-determining step (RDS) kinetic isotope effect (KIE) 9.0.

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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Ru^II-Complexes of heteroditopic chelating NHC ligands: effective catalysts for the β-alkylation of secondary alcohols and the synthesis of 2-alkylaminoquinoline derivatives following the dehydrogenative protocol

Organic & Biomolecular Chemistry, Journal Year: 2022, Volume and Issue: 20(9), P. 1945 - 1951

Published: Jan. 1, 2022

Ru II -Complexes of a heteroditopic NHC ligand, featuring ImNHC and tzNHC donors, were noted to be very efficient catalysts (up 0.001 mol%) for β-alkylation secondary alcohols one pot synthesis diverse 2-alkylaminoquinoline derivatives.

Language: Английский

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Cyclic Amide-Anchored NHC-Based Cp*Ir Catalysts for Bidirectional Hydrogenation–Dehydrogenation with CO₂/HCO₂H Couple

Organometallics, Journal Year: 2022, Volume and Issue: 41(23), P. 3589 - 3599

Published: Nov. 10, 2022

H2 storage in carbon dioxide (CO2) or bicarbonate (HCO3–) the form of formic acid (HCO2H) formate (HCO2–) and reverse liberation allows, principle, to develop a rechargeable hydrogen carrier system along with CO2-recycling mechanism. The key such an alluring approach toward realization carbon-neutral H2-based fuel option is development efficient bidirectional catalysts for CO2 (or HCO3–) hydrogenation HCO2H HCO2–) dehydrogenation. With aim (i) structurally robust under variable reaction conditions, (ii) metal–ligand bifunctionality-triggered heterolytic splitting H+/H– transfer during hydrogenation/dehydrogenation reactions, (iii) electron-rich catalytic metal center facilitating hydride delivery, (iv) water solubility via second coordination sphere interactions, herein, we applied series "cyclic amide–NHC" hybrid bidentate ligand-bound Cp*Ir(III) complexes (Ir-1–Ir-4) hydrogenation–dehydrogenation (HCO3–)/HCO2H couple as "green" solvent without use organic additives/solvents. Notably, catalyst Ir-1, achieving turnover number (TON) 16 680 at 60 °C 6 h dehydrogenation frequency (TOF5min) 70 674 h–1 80 can be efficiently carried out. Key control mechanistic studies emphasized following aspects current system: pH solution played crucial role controlling rate was cleaved readily by iridium intermediate, which could react furnish product, (acid/base)-switchable on-demand devised, liberated gas from Ir-1-catalyzed were reutilized secondary reactions tandem fashion, signifying suitability demonstrate utility typical H2/CO2 liquid, it advocated for.

Language: Английский

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Quinoline-derived NNP-manganese complex catalyzed α-alkylation of ketones with primary alcohols

Organic & Biomolecular Chemistry, Journal Year: 2024, Volume and Issue: 22(25), P. 5112 - 5116

Published: Jan. 1, 2024

An air-stable quinoline-derived NNP ligand chelated Mn catalyst was developed for the efficient α-alkylation of ketones with primary alcohols

Language: Английский

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Polyaniline-Supported Tungsten-Catalyzed α-H Alkylation Reaction of Ketone with Alcohol

Organic Letters, Journal Year: 2023, Volume and Issue: 25(43), P. 7928 - 7932

Published: Oct. 23, 2023

α-H alkylation of carbonyls is a significant reaction in the pharmaceutical industry because it can directly form C–C bond an environmentally benign manner. Thus, developing novel catalyst for this hot and practical topic catalysis, organic synthesis, materials science. In paper, we found that polyaniline-supported tungsten could catalyze ketone with alcohol generating water as only byproduct. Polyaniline support key promoting catalytic activity tungsten, which relatively cheaper than traditionally employed noble metals. The occurred under mild conditions wide substrate scope. initial concentration was enhanced to 1 mol/L, while speed accelerated reduce time 6 h; these improvements significantly enhance production capacity. advantages make synthesis industrial purposes.

Language: Английский

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Multistimuli‐Responsive [3]Dioxaphosphaferrocenophanes with Orthogonal Switches

Chemistry - A European Journal, Journal Year: 2021, Volume and Issue: 27(61), P. 15067 - 15074

Published: Aug. 30, 2021

Novel multistimuli-responsive phosphine ligands comprising a redox-active [3]dioxaphosphaferrocenophane backbone and P-bound imidazolin-2-ylidenamino entity that allows switching by protonation are reported. Investigation of the corresponding metal complexes their redox behaviour reported show sensitivity system towards coordination. The experimental findings supported DFT calculations. Protonation oxidation events applied in Rh-catalysed hydrosilylations demonstrate remarkable influence on reactivity and/or selectivity.

Language: Английский

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A Protic Mn(I) Complex Based on a Naphthyridine-N-oxide Scaffold: Protonation/Deprotonation Studies and Catalytic Applications for Alkylation of Ketones

Organometallics, Journal Year: 2022, Volume and Issue: 41(14), P. 1836 - 1846

Published: March 31, 2022

A Mn(I) complex (1) bearing a proton responsive hydroxy unit on 1,8-naphthyridine-N-oxide scaffold (L1H) was synthesized. The molecular structure of 1 revealed the lactim form ligand. corresponding deprotonated lactam complexes [18-C-6-K·2] and 3 were prepared structurally characterized. acid–base equilibrium between forms studied by 1H NMR UV–vis spectra. catalytic efficiency evaluated performing α-alkylation reaction ketones with primary alcohols. scope is broad in terms both efficacy protic catalyst demonstrated alkylation bioactive steroids progesterone pregnenolone. controlled [Mn(L2)(CO)3Br] (4), which similar to but devoid unit, shows significantly reduced validating crucial role functionality 1. Kinetic study, control reactions, deuterium labeling experiments conducted gain mechanistic insights.

Language: Английский

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Efficient β-alkylation of secondary alcohols to α-substituted ketones catalyzed by functionalized Ir complexes via borrowing hydrogen in water

Organic Chemistry Frontiers, Journal Year: 2022, Volume and Issue: 10(2), P. 355 - 362

Published: Nov. 22, 2022

Highly efficient and selective alkylation via borrowing hydrogen in water was achieved with a functional Ir complex bearing an amidate ligand. The significant cooperation effect of the ligand on high efficiency selectivity demonstrated.

Language: Английский

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Ru(II) Complexes with Protic‐ and Anionic‐Naked‐NHC Ligands for Cooperative Activation of Small Molecules**

Chemistry - A European Journal, Journal Year: 2023, Volume and Issue: 29(52)

Published: June 28, 2023

Abstract A set of ruthenium(II)‐protic‐N‐heterocyclic carbene complexes, [Ru(NNC H )(PPh 3 ) 2 (X)]Cl ( 1 , X=Cl and X=H) their deprotonated forms [Ru(NNC)(PPh (X)] ’, X=H), in which NNC is a new unsymmetrical pincer ligand, are reported. The four complexes interconvertible by simple acid‐base chemistry. combined theoretical spectroscopic investigations indicate charge segregation anionic‐NHC ’ ’) can be described from Lewis pair perspective. chemical reactivity complex shows cooperative small molecule activation. Complex activates H−H bond hydrogen, C(sp )‐I iodomethane, C(sp)‐H phenylacetylene. activation CO using anionic NHC at moderate temperature ambient pressure subsequent conversion to formate also described. All the compounds have been characterized ESI‐MS, H, 13 C, 31 P NMR spectroscopy. Molecular structures determined with single‐crystal X‐ray diffraction. perspective broadens scope potential applications activation, including carbon dioxide formate, much sought after reaction renewable energy sustainable development domains.

Language: Английский

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