Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Probing the Electronic Demands of Transmetalation in the Palladium-Catalyzed Cross-Coupling of Arylsilanolates.

ABSTRACT: The electronic characteristics of coupling partners in the transmetalation step for the cross-coupling reaction of arylsilanolates have been investigated. The ability to interrogate the transmetalation event by in situ preparation of the arylpalladium(II) silanolate intermediate has enabled a Hammett analysis for both the aryl electrophile and arylsilanolate to be conducted. These studies reveal that electron-donating groups on the silicon nucleophile and electron-withdrawing groups on the electrophile accelerate the transmetalation process.

SUBMITTER: Denmark SE

PROVIDER: S-EPMC3126151 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Probing the Electronic Demands of Transmetalation in the Palladium-Catalyzed Cross-Coupling of Arylsilanolates.

Denmark Scott E SE Smith Russell C RC Chang Wen-Tau T WT

Tetrahedron 20110601 24

The electronic characteristics of coupling partners in the transmetalation step for the cross-coupling reaction of arylsilanolates have been investigated. The ability to interrogate the transmetalation event by in situ preparation of the arylpalladium(II) silanolate intermediate has enabled a Hammett analysis for both the aryl electrophile and arylsilanolate to be conducted. These studies reveal that electron-donating groups on the silicon nucleophile and electron-withdrawing groups on the elect ...[more]

PMID: 21731114

Similar Datasets

Insight into Transmetalation Enables Cobalt-Catalyzed Suzuki-Miyaura Cross Coupling.

Project description:Among the fundamental transformations that comprise a catalytic cycle for cross coupling, transmetalation from the nucleophile to the metal catalyst is perhaps the least understood. Optimizing this elementary step has enabled the first example of a cobalt-catalyzed Suzuki-Miyaura cross coupling between aryl triflate electrophiles and heteroaryl boron nucleophiles. Key to this discovery was the preparation and characterization of a new class of tetrahedral, high-spin bis(phosphino)pyridine cobalt(I) alkoxide and aryloxide complexes, (iPrPNP)CoOR, and optimizing their reactivity with 2-benzofuranylBPin (Pin = pinacolate). Cobalt compounds with small alkoxide substituents such as R = methyl and ethyl underwent swift transmetalation at 23 °C but also proved kinetically unstable toward β-H elimination. Secondary alkoxides such as R = iPr or CH(Ph)Me balanced stability and reactivity. Isolation and structural characterization of the product following transmetalation, (iPrPNP)Co(2-benzofuranyl), established a planar, diamagnetic cobalt(I) complex, demonstrating the high- and low-spin states of cobalt(I) rapidly interconvert during this reaction. The insights from the studies in this elementary step guided selection of appropriate reaction conditions to enable the first examples of cobalt-catalyzed C-C bond formation between neutral boron nucleophiles and aryl triflate electrophiles, and a model for the successful transmetalation reactivity is proposed.

| S-EPMC5200927 | biostudies-literature

Phosphino-Triazole Ligands for Palladium-Catalyzed Cross-Coupling.

Project description:Twelve 1,5-disubtituted and fourteen 5-substituted 1,2,3-triazole derivatives bearing diaryl or dialkyl phosphines at the 5-position were synthesized and used as ligands for palladium-catalyzed Suzuki-Miyaura cross-coupling reactions. Bulky substrates were tested, and lead-like product formation was demonstrated. The online tool SambVca2.0 was used to assess steric parameters of ligands and preliminary buried volume determination using XRD-obtained data in a small number of cases proved to be informative. Two modeling approaches were compared for the determination of the buried volume of ligands where XRD data was not available. An approach with imposed steric restrictions was found to be superior in leading to buried volume determinations that closely correlate with observed reaction conversions. The online tool LLAMA was used to determine lead-likeness of potential Suzuki-Miyaura cross-coupling products, from which 10 of the most lead-like were successfully synthesized. Thus, confirming these readily accessible triazole-containing phosphines as highly suitable ligands for reaction screening and optimization in drug discovery campaigns.

| S-EPMC6265957 | biostudies-literature

Palladium-Catalyzed C-O Cross-Coupling of Primary Alcohols.

Project description:Two catalyst systems are described, which together provide mild and general conditions for the Pd-catalyzed C-O cross-coupling of primary alcohols. For activated substrates, such as electron-deficient aryl halides, the commercially available ligand L2 promotes efficient coupling for a variety of alcohol nucleophiles. In the case of unactivated electrophiles, such as electron-rich aryl halides, the new ligand L8 was developed to improve these challenging C-O bond-forming reactions.

| S-EPMC5856650 | biostudies-literature

Regioselective Palladium-Catalyzed Cross-Coupling Reactions of 2,4,7-Trichloroquinazoline.

Project description:The regioselective palladium-catalyzed cross-coupling reactions of 2,4,7-trichloroquinazoline with various aryl- and heteroarylboronic acids are reported. An efficient, sequential strategy was developed that provides access to novel, functionalized heterocycles.

| S-EPMC2992347 | biostudies-literature

Palladium-Catalyzed Cross-Coupling of Monochlorosilanes And Grignard Reagents.

Project description:Using a palladium catalyst supported by DrewPhos, the alkylation of monochlorosilanes with primary and secondary alkyl-magnesium halides is now possible. Arylation with sterically demanding aromatic magnesium halides is also enabled. This transformation overcomes the high bond strength of the Si-Cl bond (113 kcal/mol) and is a rare example of a transition-metal catalyzed process involving its activation. Due to the availability of both chlorosilanes and organomagnesium halide reagents, this method allows for the preparation of a wide range of alkyl and aryl silanes.

| S-EPMC5984048 | biostudies-literature

Efficient palladium-catalyzed cross-coupling of highly acidic substrates, nitroacetates.

Project description:Palladium-catalyzed cross-coupling conditions were developed that efficiently afford 2-aryl-2-nitroacetates from aryl bromides and the very acidic nitroacetates.

| S-EPMC3289998 | biostudies-literature

Palladium and Nickel Catalyzed Suzuki Cross-Coupling with Alkyl Fluorides.

Project description:Suzuki cross-coupling of benzylic and unactivated aliphatic fluorides with aryl- and alkenylboronic acids has been achieved via mechanistically distinct Pd and Ni catalyzed pathways that outperform competing protodeboronation, β-hydride elimination, and homocoupling processes. The utility is demonstrated with more than 20 examples including heterocyclic structures, 1,1-disubstituted and trans-1,2-disubstituted alkenes, and by the incorporation of acetonitrile into functionalized (hetero)arenes.

| S-EPMC8987895 | biostudies-literature

Recyclable polystyrene-supported siloxane-transfer agent for palladium-catalyzed cross-coupling reactions.

Project description:The rational design, synthesis, and validation of a significantly improved insoluble polymer-supported siloxane-transfer agent has been achieved that permits efficient palladium-catalyzed cross-coupling reactions. The cross-linked polystyrene support facilitates product purification with excellent siloxane recycling. Drawbacks of a previous polymer-supported siloxane-transfer agent, relating to reaction efficiency and polymer stability after repeated cycles, have been addressed.

| S-EPMC3993864 | biostudies-other

Palladium catalyzed radical relay for the oxidative cross-coupling of quinolines.

Project description:Traditional approaches for transition-metal catalyzed oxidative cross-coupling reactions rely on sp2-hybridized starting materials, such as aryl halides, and more specifically, homogeneous catalysts. We report a heterogeneous Pd-catalyzed radical relay method for the conversion of a heteroarene C(sp3)-H bond into ethers. Pd nanoparticles are supported on an ordered mesoporous composite which, when compared with microporous activated carbons, greatly increases the Pd d charge because of their strong interaction with N-doped anatase nanocrystals. Mechanistic studies provide evidence that electron-deficient Pd with Pd-O/N coordinations efficiently catalyzes the radical relay reaction to release diffusible methoxyl radicals, and highlight the difference between this surface reaction and C-H oxidation mediated by homogeneous catalysts that operate with cyclopalladated intermediates. The reactions proceed efficiently with a turn-over frequency of 84 h-1 and high selectivity toward ethers of >99%. Negligible Pd leaching and activity loss are observed after 7 catalytic runs.

| S-EPMC9296488 | biostudies-literature

Understanding Site Selectivity in the Palladium-Catalyzed Cross-Coupling of Allenylsilanolates.

Project description:Allenylsilanolates can undergo cross-coupling at the α- or γ-terminus, and site selectivity appears to be determined by the intrinsic transmetalation mechanism. Fine-tuning of concentration, nucleophilicity, and steric bulk of the silanolate moiety allows for the selective formation of one isomer over the other. Whereas the α-isomer can be obtained in synthetically useful yield, the γ-isomer is favored only when employing reaction conditions that are inevitably associated with diminished reactivity.

| S-EPMC5997285 | 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