Browse
Submit Data
Databases
API
Help

Dataset Information

27 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Facilitating Gold Redox Catalysis with Electrochemistry: An Efficient Chemical-Oxidant-Free Approach.

ABSTRACT: Due to the high oxidation potential between AuI and AuIII , gold redox catalysis requires at least stoichiometric amounts of a strong oxidant. We herein report the first example of an electrochemical approach in promoting gold-catalyzed oxidative coupling of terminal alkynes. Oxidation of AuI to AuIII was successfully achieved through anode oxidation, which enabled facile access to either symmetrical or unsymmetrical conjugated diynes through homo-coupling or cross-coupling. This report extends the reaction scope of this transformation to substrates that are not compatible with strong chemical oxidants and potentiates the versatility of gold redox chemistry through the utilization of electrochemical oxidative conditions.

SUBMITTER: Ye X

PROVIDER: S-EPMC7137689 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Facilitating Gold Redox Catalysis with Electrochemistry: An Efficient Chemical-Oxidant-Free Approach.

Ye Xiaohan X Zhao Pengyi P Zhang Shuyao S Zhang Yanbin Y Wang Qilin Q Shan Chuan C Wojtas Lukasz L Guo Hao H Chen Hao H Shi Xiaodong X

Angewandte Chemie (International ed. in English) 20190904 48

Due to the high oxidation potential between AuI and AuIII , gold redox catalysis requires at least stoichiometric amounts of a strong oxidant. We herein report the first example of an electrochemical approach in promoting gold-catalyzed oxidative coupling of terminal alkynes. Oxidation of AuI to AuIII was successfully achieved through anode oxidation, which enabled facile access to either symmetrical or unsymmetrical conjugated diynes through homo-coup ...[more]

PMID: 31407454

Similar Datasets

Gold Redox Catalysis with a Selenium Cation as a Mild Oxidant.

Project description:Gold-catalyzed alkyne and allene diselenations were developed. Excellent regioselectivity (trans) and good to excellent yields were achieved (up to 98 % with 2 % catalyst loading) with a wide range of substrates. Mechanistic investigation revealed the formation of a vinyl gold(I) intermediate followed by an intermolecular selenium cation migration, suggesting that a gold(I/III) redox process was successfully implemented under mild conditions.

| S-EPMC7220824 | biostudies-literature

Highly Efficient and Stereoselective Thioallylation of Alkynes: Possible Gold Redox Catalysis with No Need for a Strong Oxidant.

Project description:Stereoselective thioallylation of alkynes under possible gold redox catalysis was accomplished with high efficiency (as low as 0.1?% catalyst loading, up to 99?% yield) and broad substrate scope (various alkynes, inter- and intramolecular fashion). The gold(I) catalyst acts as both a ?-acid for alkyne activation and a redox catalyst for AuI/III coupling, whereas the sulfonium cation generated in situ functions as a mild oxidant. This novel methodology provides an exciting system for gold redox catalysis without the need for a strong oxidant.

| S-EPMC6121218 | biostudies-literature

Redox-Rich Metallocene Tetrazene Complexes: Synthesis, Structure, Electrochemistry, and Catalysis.

Project description:Thermal or photochemical metal-centered cycloaddition reactions of azidocobaltocenium hexafluoridophosphate or azidoferrocene with (cyclooctadiene)(cyclopentadienyl)cobalt(I) afforded the first metallocenyl-substituted tetrazene cyclopentadienyl cobalt complexes together with azocobaltocenium or azoferrocene as side products. The trimetallic CpCo compounds are highly conjugated, colored, and redox-active metallo-aromatic compounds, as shown by their spectroscopic, structural, and electrochemical properties. The CpCo-tetrazenido complex with two terminally appended cobaltocene units catalyzes electrochemical proton reduction from acetic acid at a mild overpotential (0.35 V). Replacing cobaltocene with ferrocene moieties rendered the complex inactive toward catalysis.

| S-EPMC6437651 | biostudies-literature

Nanoporous Gold: From Structure Evolution to Functional Properties in Catalysis and Electrochemistry.

Project description:Nanoporous gold (NPG) is characterized by a bicontinuous network of nanometer-sized metallic struts and interconnected pores formed spontaneously by oxidative dissolution of the less noble element from gold alloys. The resulting material exhibits decent catalytic activity for low-temperature, aerobic total as well as partial oxidation reactions, the oxidative coupling of methanol to methyl formate being the prototypical example. This review not only provides a critical discussion of ways to tune the morphology and composition of this material and its implication for catalysis and electrocatalysis, but will also exemplarily review the current mechanistic understanding of the partial oxidation of methanol using information from quantum chemical studies, model studies on single-crystal surfaces, gas phase catalysis, aerobic liquid phase oxidation, and electrocatalysis. In this respect, a particular focus will be on mechanistic aspects not well understood, yet. Apart from the mechanistic aspects of catalysis, best practice examples with respect to material preparation and characterization will be discussed. These can improve the reproducibility of the materials property such as the catalytic activity and selectivity as well as the scope of reactions being identified as the main challenges for a broader application of NPG in target-oriented organic synthesis.

| S-EPMC10214458 | biostudies-literature

Electrochemical gold redox catalysis for selective oxidative arylation.

Project description:The combination of ArB(OH)2 transmetallation with cationic gold(I) [LAu]+ and electrochemical anodic oxidation (EAO) approach was successfully developed for the preparation of AuIII-Ar intermediate for the first time. This in-situ generated aryl gold intermediate gave rapid and controllable transmetallation with ArB(OH)2 or alkyne followed by reductive elimination to generate either di-aryl coupling or sp2-sp Sonogashira-type coupling products under mild conditions with no need of external oxidants, which significantly extended the versatility of electrochemical approach in promoting gold redox catalysis.

| S-EPMC10723655 | biostudies-literature

Combining Zn Ion Catalysis with Homogeneous Gold Catalysis: An Efficient Annulation Approach to N-Protected Indoles.

Project description:The Fischer indole synthesis is perhaps the most powerful method for indole preparation, but it often suffers from low regioselectivities with unsymmetric aliphatic ketone substrates and strong acidic conditions and is not suitable for α,β-unsaturated ketones. In this article, we disclose an efficient synthesis of N-protected indoles from N-arylhydroxamic acids/N-aryl-N-hydroxycarbamates and a variety of alkynes via a cooperative gold and zinc catalysis. The zinc catalysis is similar to the related zinc ion catalysis in metalloenzymes such as human carbonic anhydrase II and substantially enhances the O-nucleophilicity of N-acylated hydroxamines by forming the corresponding Zn chelates. The Zn chelates can attack gold-activated alkynes to form O-alkenyl-N-arylhydroxamates, which can undergo facile 3,3-sigmatropic rearrangements and subsequent cyclodehydrations to yield N-protected indole products. This new chemistry offers several important improvements over the Fischer indole synthesis: a) the reaction conditions are mildly acidic and can tolerate sensitive groups such as Boc; b) broader substrate scopes including substrates with pendant carbonyl groups (reactive in the Fischer chemistry) and alkyl chlorides (e.g., 3f); c) better regioselectivities for the formation of 2-substituted indoles under much milder conditions; d) 2-alkenylindoles can be prepared readily in good to excellent yields, but the Fischer chemistry could not; e) with internal alkynes both steric and electronic controls are available for achieving good regioselectivities, while the Fischer chemistry is in general problematic.

| S-EPMC3826563 | biostudies-literature

Photoexcited Ru single-atomic sites for efficient biomimetic redox catalysis.

Project description:The unsatisfactory catalytic activity of nanozymes owing to their inefficient electron transfer (ET) is the major challenge in biomimetic catalysis-related biomedical applications. Inspired by the photoelectron transfers in natural photoenzymes, we herein report a photonanozyme of single-atom Ru anchored on metal-organic frameworks (UiO-67-Ru) for achieving photoenhanced peroxidase (POD)-like activity. We demonstrate that the atomically dispersed Ru sites can realize high photoelectric conversion efficiency, superior POD-like activity (7.0-fold photoactivity enhancement relative to that of UiO-67), and good catalytic specificity. Both in situ experiments and theoretical calculations reveal that photoelectrons follow the cofactor-mediated ET process of enzymes to promote the production of active intermediates and the release of products, demonstrating more favorable thermodynamics and kinetics in H2O2 reduction. Taking advantage of the unique interaction of the Zr-O-P bond, we establish a UiO-67-Ru-based immunoassay platform for the photoenhanced detection of organophosphorus pesticides.

| S-EPMC10214184 | biostudies-literature

Gold redox catalysis for cyclization/arylation of allylic oximes: synthesis of isoxazoline derivatives.

Project description:Base-assisted diazonium activation has been employed to promote gold(i)/(iii) redox catalysis toward allylic oxime cyclization/aryl coupling. Functional isoxazolines were prepared with good to excellent yields, while the alternative photoactivation method provided trace amounts of the isoxazoline products. This study further broadens the scope of gold redox chemistry.

| S-EPMC6641983 | biostudies-literature

Au(iii)-aryl intermediates in oxidant-free C-N and C-O cross-coupling catalysis.

Project description:Au(iii)-aryl species have been unequivocally identified as reactive intermediates in oxidant-free C-O and C-N cross coupling catalysis. The crystal structures of cyclometalated neutral and cationic Au(iii) species are described and their key role in 2 electron-redox Au(i)/Au(iii) catalysis in C-O and C-N cross couplings is shown. Nucleophiles compatible with Au-catalyzed cross couplings include aromatic and aliphatic alcohols and amines, as well as water and amides.

| S-EPMC5452266 | biostudies-literature

Triple the fun: tris(ferrocenyl)arene-based gold(i) complexes for redox-switchable catalysis.

Project description:The modular syntheses of C 3-symmetric tris(ferrocenyl)arene-based tris-phosphanes and their homotrinuclear gold(i) complexes are reported. Choosing the arene core allows fine-tuning of the exact oxidation potentials and thus tailoring of the electrochemical response. The tris[chloridogold(i)] complexes were investigated in the catalytic ring-closing isomerisation of N-(2-propyn-1-yl)benzamide, showing cooperative behaviour vs. a mononuclear chloridogold(i) complex. Adding one, two, or three equivalents of 1,1'-diacetylferrocenium[tetrakis(perfluoro-tert-butoxy)aluminate] as an oxidant during the catalytic reaction (in situ) resulted in a distinct, stepwise influence on the resulting catalytic rates. Isolation of the oxidised species is possible, and using them as (pre-)catalysts (ex situ oxidation) confirmed the activity trend. Proving the intactness of the P-Au-Cl motif during oxidation, the tri-oxidised benzene-based complex has been structurally characterised.

| S-EPMC8162263 | 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