Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Reactions of Imines with Azazirconacyclobutenes and Generation of Electron-Deficient Imidozirconocene Complexes.

ABSTRACT: Electron-deficient imines are shown to insert into the zirconium-carbon bond of azazirconacyclobutenes to generate new six-membered ring metallacycles. On heating, these expanded zirconacycles undergo a retro-[4 + 2] cycloaddition to generate alpha,beta-unsaturated imines in excellent yields and novel, fully characterized electron-deficient imidozirconocene complexes.

SUBMITTER: Ruck RT

PROVIDER: S-EPMC1383655 | biostudies-literature | 2004 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Reactions of Imines with Azazirconacyclobutenes and Generation of Electron-Deficient Imidozirconocene Complexes.

Ruck Rebecca T RT Bergman Robert G RG

Organometallics 20040501 10

Electron-deficient imines are shown to insert into the zirconium-carbon bond of azazirconacyclobutenes to generate new six-membered ring metallacycles. On heating, these expanded zirconacycles undergo a retro-[4 + 2] cycloaddition to generate alpha,beta-unsaturated imines in excellent yields and novel, fully characterized electron-deficient imidozirconocene complexes. ...[more]

PMID: 16508694

Similar Datasets

Synthesis of highly substituted benzene ring systems through three-component coupling of enyne imines, Fischer carbene complexes, and electron-deficient alkynes.

Project description:Three-component coupling of Fischer carbene complexes, enyne aldehyde hydrazones, and electron-deficient alkynes leads to simple benzoate derivatives in a process involving the formation of an N-aminopyrrole derivative, Diels-Alder reaction, and nitrene extrusion. The products are readily converted into isoquinolones through reaction with primary amines. The reaction proceeds best with highly substituted and electron-rich pyrroles even though these are the sterically least favorable substrates, and this reactivity trend is supported by a computational study.

| S-EPMC5619673 | biostudies-literature

Transmetalation Reactions Triggered by Electron Transfer between Organocopper Complexes.

Project description:[Cu(bipy)(C6F5)] reacts with most aryl iodides to form heterobiphenyls by cross-coupling, but when Rf-I is used (Rf = 3,5-dicholoro-2,4,6-trifluorophenyl), homocoupling products are also formed. Kinetic studies suggest that, for the homocoupling reaction, a mechanism based on transmetalation from [Cu(bipy)(C6F5)] to Cu(III) intermediates formed in the oxidative addition step is at work. Density functional theory calculations show that the interaction between these Cu(III) species and the starting Cu(I) complex involves a Cu(I)-Cu(III) electron transfer concerted with the formation of an iodine bridge between the metals and that a fast transmetalation takes place in a dimer in a triplet state between two Cu(II) units.

| S-EPMC8609523 | biostudies-literature

Electron-Deficient Imidazolium Substituted Cp Ligands and their Ru Complexes.

Project description:The synthesis of electron-poor mono-, di- and tri(imidazolium)-substituted Cp-ylides is presented and their electronic properties are discussed based on NMR spectroscopy, X-ray structure analyses, electrochemical investigations and DFT calculations as well as by their reactivity toward [Ru(CH3 CN)3 Cp*](PF6 ). With mono- and di(imidazolium)-substituted cyclopentadienides the respective monocationic and dicationic ruthenocences are formed (X-ray), whereas tri(imidazolium) cyclopentadienides are too electron-poor to form the ruthenocenes. Cyclic voltammetric analysis of the ruthenocenes shows reversible oxidation at a potential that increases with every additional electron-withdrawing imidazolium substituent at the Cp ligand by 0.53-0.55 V in an electrolyte based on a weakly coordinating anion. A reversible oxidation can be observed for the free 1,3-disubstituted ligand as well.

| S-EPMC7756557 | biostudies-literature

Catalytic asymmetric umpolung reactions of imines.

Project description:The carbon-nitrogen double bonds in imines are fundamentally important functional groups in organic chemistry. This is largely due to the fact that imines act as electrophiles towards carbon nucleophiles in reactions that form carbon-carbon bonds, thereby serving as one of the most widely used precursors for the formation of amines in both synthetic and biosynthetic settings. If the carbon atom of the imine could be rendered electron-rich, the imine could react as a nucleophile instead of as an electrophile. Such a reversal in the electronic characteristics of the imine functionality would facilitate the development of new chemical transformations that convert imines into amines via carbon-carbon bond-forming reactions with carbon electrophiles, thereby creating new opportunities for the efficient synthesis of amines. The development of asymmetric umpolung reactions of imines (in which the imines act as nucleophiles) remains uncharted territory, in spite of the far-reaching impact such reactions would have in organic synthesis. Here we report the discovery and development of new chiral phase-transfer catalysts that promote the highly efficient asymmetric umpolung reactions of imines with the carbon electrophile enals. These catalysts mediate the deprotonation of imines and direct the 2-azaallyl anions thus formed to react with enals in a highly chemoselective, regioselective, diastereoselective and enantioselective fashion. The reaction tolerates a broad range of imines and enals, and can be carried out in high yield with as little as 0.01 mole per cent catalyst with a moisture- and air-tolerant operational protocol. These umpolung reactions provide a conceptually new and practical approach to chiral amino compounds.

| S-EPMC4513368 | biostudies-literature

Interfacial Covalent Bonds Regulated Electron-Deficient 2D Black Phosphorus for Electrocatalytic Oxygen Reactions.

Project description:Developing resource-abundant and sustainable metal-free bifunctional oxygen electrocatalysts is essential for the practical application of zinc-air batteries (ZABs). 2D black phosphorus (BP) with fully exposed atoms and active lone pair electrons can be promising for oxygen electrocatalysts, which, however, suffers from low catalytic activity and poor electrochemical stability. Herein, guided by density functional theory (DFT) calculations, an efficient metal-free electrocatalyst is demonstrated via covalently bonding BP nanosheets with graphitic carbon nitride (denoted BP-CN-c). The polarized PN covalent bonds in BP-CN-c can efficiently regulate the electron transfer from BP to graphitic carbon nitride and significantly promote the OOH* adsorption on phosphorus atoms. Impressively, the oxygen evolution reaction performance of BP-CN-c (overpotential of 350 mV at 10 mA cm-2 , 90% retention after 10 h operation) represents the state-of-the-art among the reported BP-based metal-free catalysts. Additionally, BP-CN-c exhibits a small half-wave overpotential of 390 mV for oxygen reduction reaction, representing the first bifunctional BP-based metal-free oxygen catalyst. Moreover, ZABs are assembled incorporating BP-CN-c cathodes, delivering a substantially higher peak power density (168.3 mW cm-2 ) than the Pt/C+RuO2 -based ZABs (101.3 mW cm-2 ). The acquired insights into interfacial covalent bonds pave the way for the rational design of new and affordable metal-free catalysts.

| S-EPMC11469023 | biostudies-literature

Elucidating electron-transfer events in polypyridine nickel complexes for reductive coupling reactions.

Project description:Polypyridine-ligated nickel complexes are widely used as privileged catalysts in a variety of cross-coupling reactions. The rapid adoption of these complexes is tentatively attributed to their ability to shuttle between different oxidation states and engage in electron-transfer reactions. However, these reactions are poorly understood in mechanistic terms. Here we investigate the reactivity of pseudohalide- and halide-ligated Ni(II) complexes, containing polypyridine ligands, in electron-transfer reactions. Specifically, Ni(II) halide complexes trigger comproportionation with Ni(0) with exceptional ease en route to Ni(I)L n species, whereas the corresponding Ni(II) pseudohalide congeners are resistant to electron transfer, with Ni(I) pseudohalides being prone to disproportionation events. These observations are corroborated by electrochemical techniques and detailed quantum mechanical calculations. We also show that catalytically inactive Ni(II) pseudohalide complexes can be reactivated in the presence of exogeneous salts. From a broader perspective, this study provides rationalizations for overlooked and fundamental steps within the Ni-catalysed cross-coupling arena, thus offering blueprints for designing future Ni-catalysed reactions.

| S-EPMC11546168 | biostudies-literature

The Pd-catalysed asymmetric allylic alkylation reactions of sulfamidate imines.

Project description:The Pd-catalysed asymmetric allylic alkylation (Pd-AAA) of prochiral enamide anions derived from 5H-oxathiazole 2,2-dioxides has been developed. Various 4,5-disubstituted and 4-substituted cyclic sulfamidate imines have participated in the transformation with a range of allyl carbonates-as well as 2-vinyl oxirane, 2-vinyl-N-tosylaziridine, and 2-vinyl-1,1-cyclopropane dicarboxylate-to furnish the desired C-allylated products in moderate to high yields, with high regioselectivites and generally high enantioselectivities. Conversion between N- and C-allyl products was observed, with the N-allylated products converting to the C-allylated products over time. The resulting high-value allylated heterocyclic products all bear a tetrasubstituted stereogenic centre and can be reduced to an allylated chiral sulfamidate or an amino alcohol.

| S-EPMC8494038 | biostudies-literature

Photodetachment photoelectron spectroscopy shows isomer-specific proton-coupled electron transfer reactions in phenolic nitrate complexes.

Project description:The oxidation of phenolic compounds is one of the most important reactions prevalent in various biological processes, often explicitly coupled with proton transfers (PTs). Quantitative descriptions and molecular-level understanding of these proton-coupled electron transfer (PCET) reactions have been challenging. This work reports a direct observation of PCET in photodetachment (PD) photoelectron spectroscopy (PES) of hydrogen-bonded phenolic (ArOH) nitrate (NO3-) complexes, in which a much slower rising edge provides a spectroscopic signature to evidence PCET. Electronic structure calculations unveil the PCET processes to be isomer-specific, occurred only in those with their HOMOs localized on ArOH, leading to charge-separated transient states ArOH•+·NO3- triggered by ionizing phenols while simultaneously promoting PT from ArOH•+ to NO3-. Importantly, this study showcases that gas-phase PD-PES is a generic means enabling to identify PCET reactions with explicit structural and binding information.

| S-EPMC11315994 | biostudies-literature

Highly electron-deficient 3,6-diaza-9-borafluorene scaffolds for the construction of luminescent chelate complexes.

Project description:The synthesis and characterization of two fluorinated 3,6-diaza-9-hydroxy-9-borafluorene oxonium acids featuring improved hydrolytic stability and the strong electron-deficient character of the diazaborafluorene core is reported. These boracycles served as precursors of fluorescent spiro-type complexes with (O,N)-chelating ligands which revealed specific properties such as delayed emission, white light emission in the solid state and photocatalytic performance in singlet oxygen-mediated oxidation reactions.

| S-EPMC10631248 | biostudies-literature

Highly electron-deficient 1-propyl-3,5-dinitropyridinium: evaluation of electron-accepting ability and application as an oxidative quencher for metal complexes.

Project description:Impacts of the nitro groups on the electron-accepting and oxidizing abilities of N-propylpyridinium were evaluated quantitatively. A 3,5-dinitro derivative has efficiently quenched emission from photosensitizing Ru(ii) and Ir(iii) complexes owing to the thermodynamically-favored electron transfer to the pyridinium whose LUMO is greatly lowered by the presence of electron-withdrawing nitro groups.

| S-EPMC10865184 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data