Browse
Submit Data
Databases
API
Help

Dataset Information

19 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Pd-catalyzed aerobic oxidative coupling of arenes: evidence for transmetalation between two Pd(II)-aryl intermediates.

ABSTRACT: Pd-catalyzed aerobic oxidative coupling of arenes provides efficient access to biaryl compounds. The biaryl product forms via C-H activation of two arenes to afford a Pd(II)ArAr' intermediate, which then undergoes C-C reductive elimination. The key Pd(II)ArAr' intermediate could form via a "monometallic" pathway involving sequential C-H activation at a single Pd(II) center, or via a "bimetallic" pathway involving parallel C-H activation at separate Pd(II) centers, followed by a transmetalation step between two Pd(II)-aryl intermediates. Here, we investigate the oxidative coupling of o-xylene catalyzed by a PdX2/2-fluoropyridine catalyst (X = trifluoroacetate, acetate). Kinetic studies, H/D exchange experiments, and kinetic isotope effects provide clear support for a bimetallic/transmetalation mechanism.

SUBMITTER: Wang D

PROVIDER: S-EPMC4161672 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Kinetic and Spectroscopic Studies of Aerobic Copper(II)-Catalyzed Methoxylation of Arylboronic Esters and Insights into Aryl Transmetalation to Copper(II).

Project description:We previously reported a preliminary mechanistic study of aerobic Cu(OAc)(2)-catalyzed methoxylation of 4-tolylboronic ester (King, et al. J. Am. Chem. Soc., 2009, 131, 5044-5045), which revealed that aryl transmetalation from the boronic ester to Cu(II) is the turnover-limiting step. In the present study, more-thorough kinetic and spectroscopic studies provide additional insights into transmetalation pathway and the identity of the Cu(II) catalyst resting state(s). EPR spectroscopic studies show that at least two copper(II) species are present under catalytic conditions and their relative populations vary as a function of reaction time and acidity of the arylboronic ester, and are influenced by addition of acetic acid or acetate to the reaction mixture. Analysis of kinetic data and (11)B NMR and EPR spectra under diverse reaction conditions suggests that aryl transmetalation occurs from a tetracoordinate, anionic boronate to a cationic Cu(II) species, mediated by a methoxide-bridge.

| S-EPMC3509420 | biostudies-literature

Versatile Pd(II)-catalyzed C-H activation/aryl-aryl coupling of benzoic and phenyl acetic acids.

Project description:The use of aryltrifluoroborates as coupling partners and O(2) as the oxidant substantially improves the scope and practicality of the Pd-catalyzed C-H activation/C-C coupling reaction. The newly discovered protocol made possible, for the first time, the ortho-coupling of electron-deficient arenes and phenyl acetic acids with organometallic reagents.

| S-EPMC2630538 | biostudies-literature

Pd-Catalyzed Aerobic Oxidative Heck Cross-Coupling for the Straightforward Construction of Indole δ-Lactams.

Project description:The [6.5.6]-tricyclic indole δ-lactam represents a common key intermediate for the synthesis of a broad variety of structurally intriguing indole alkaloids. The development of a method for the versatile and straightforward construction of such structural motif is of great importance for potential synthetic applications. Herein, we present a co-ligand-prompted Pd-catalyzed 6-exo-trig intramolecular cyclization of indolyl amides via the aerobic oxidative Heck cross-coupling. The method provided a general and efficient way for the construction of [6.5.6]-tricyclic indole δ-lactams. A mechanistic study suggests that a Pd(I)/Pd(III) catalytic cycle should be responsible for effective coupling, which represents a mechanistically alternative pathway when compared with the Pd(0)/Pd(II) cycle proposed for other related coupling reactions.

| S-EPMC6637253 | biostudies-literature

Pd(II)-Catalyzed Cross-Coupling of C(sp2 )-H Bonds and Alkyl-, Aryl- and Vinyl-Boron Reagents via Pd(II)/Pd(0) Catalysis.

Project description:Pd(II)-catalyzed cross-coupling of ortho-C-H bonds in benzoic acid and phenylacetic acid amides with alkyl-, aryl- and vinyl-boron reagents have been achieved via Pd(II)/Pd(0) catalysis, demonstrating the unprecedented versatility of C-H activation reactions.

| S-EPMC3638876 | biostudies-literature

Expeditious Enyne Construction from Alkynes via Oxidative Pd(II) Catalyzed Heck-Type Coupling.

Project description:The enyne, ubiquitous in natural products, can be a challenge to generate since these moieties require many synthetic transformations to assemble them. We developed a simpler protocol to construct enynes while we found that this oxidative reaction was tolerant in substrate scope. In addition, the utility of this reaction was demonstrated through the attempt in synthesizing antifungal agent Lamisi.

| S-EPMC2796801 | biostudies-literature

Intramolecular Pd(II)-catalyzed aerobic oxidative amination of alkenes: synthesis of six-membered N-heterocycles.

Project description:Use of a base-free Pd(DMSO)(2)(TFA)(2) catalyst system enables the synthesis of six-membered nitrogen heterocycles via a Wacker-type aerobic oxidative cyclization of alkenes bearing tethered sulfonamides. Various heterocycles, including morpholines, piperidines, piperazines, and piperazinones, are accessible by this method.

| S-EPMC3298079 | biostudies-literature

Pd-catalyzed cross-coupling reactions of amides and aryl mesylates.

Project description:A catalyst, based on a biarylphosphine ligand, for the Pd-catalyzed cross-coupling reactions of amides and aryl mesylates is described. This system allows an array of aryl and heteroaryl mesylates to be transformed into the corresponding N-aryl amides in moderate to excellent yields.

| S-EPMC2874946 | biostudies-literature

Pd(II)-Catalyzed C3-Selective Arylation of Pyridine with (Hetero)arenes.

Project description:Palladium catalyzed, nondirected C3-selective arylation of pyridines with arenes and heteroarenes in the presence of 1,10-phenanthroline as the ligand has been developed. The optimized conditions allow for a highly C3-selective arylation of pyridines, affording various 3,3'-bipyridines and 3-arylpyridines.

| S-EPMC4821414 | biostudies-literature

Pd(II)-catalyzed para-selective C-H arylation of monosubstituted arenes.

Project description:Pd-catalyzed highly para-selective C-H arylation of monosubstituted arenes (including toluene) is developed for the first time using an F(+) reagent as a bystanding oxidant. This finding provides a new retrosynthetic disconnection for para-substituted biaryl synthesis via C-H/C-H cross-coupling.

| S-EPMC3345815 | biostudies-literature

Palladium(II)-catalyzed othro-C-H-benzoxylation of 2-arylpyridines by oxidative coupling with aryl acylperoxides.

Project description:A palladium(II)-catalyzed ortho-benzoxylation of 2-arylpyridines with aryl acylperoxides was developed. With pyridyl as directing group, the benzoxylation reaction exhibits remarkable regioselectivity and excellent functional group tolerance, providing the products in up to 87% yield.

| S-EPMC6270440 | 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