Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Halide-Dependent Mechanisms of Reductive Elimination from Gold(III).

ABSTRACT: Two unique organometallic halide series (Ph3P)Au(4-Me-C6H4)(CF3)(X) and (Cy3P)Au(4-F-C6H4)(CF3)(X) (X = I, Br, Cl, F) have been synthesized. The PPh3-supported complexes can undergo both C(aryl)-X and C(aryl)-CF3 reductive elimination. Mechanistic studies of thermolysis at 122 °C reveal a dramatic reactivity and kinetic selectivity dependence on halide ligand. For X = I or F, zero-order kinetic behavior is observed, while for X = Cl or Br, kinetic studies implicate product catalysis. The selectivity for C(aryl)-CF3 bond formation increases in the order X = I < Br < Cl < F, with exclusively C(aryl)-I bond formation when X = I, and exclusively C(aryl)-CF3 bond formation when X = F. Thermodynamic measurements show that Au(III)-X bond dissociation energies increase in the order X = I < Br < Cl, and that ground state Au(III)-X bond strength ultimately dictates selectivities for C(aryl)-X and C(aryl)-CF3 reductive elimination.

SUBMITTER: Winston MS

PROVIDER: S-EPMC4482415 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Halide-Dependent Mechanisms of Reductive Elimination from Gold(III).

Winston Matthew S MS Wolf William J WJ Toste F Dean FD

Journal of the American Chemical Society 20150611 24

Two unique organometallic halide series (Ph3P)Au(4-Me-C6H4)(CF3)(X) and (Cy3P)Au(4-F-C6H4)(CF3)(X) (X = I, Br, Cl, F) have been synthesized. The PPh3-supported complexes can undergo both C(aryl)-X and C(aryl)-CF3 reductive elimination. Mechanistic studies of thermolysis at 122 °C reveal a dramatic reactivity and kinetic selectivity dependence on halide ligand. For X = I or F, zero-order kinetic behavior is observed, while for X = Cl or Br, kinetic studies implicate product catalysis. The selecti ...[more]

PMID: 26065722

Similar Datasets

Exceptionally fast carbon-carbon bond reductive elimination from gold(III).

Project description:Reductive elimination of carbon-carbon bonds occurs in numerous metal-catalysed reactions. This process is well documented for a variety of transition metal complexes. However, carbon-carbon bond reductive elimination from a limited number of Au(III) complexes has been shown to be a slow and prohibitive process that generally requires elevated temperatures. Herein we show that oxidation of a series of mono- and bimetallic Au(I) aryl complexes at low temperature generates observable Au(III) and Au(II) intermediates. We also show that aryl-aryl bond reductive elimination from these oxidized species is not only among the fastest observed for any transition metal, but is also mechanistically distinct from previously studied alkyl-alkyl and aryl-alkyl reductive eliminations from Au(III).

| S-EPMC3970324 | biostudies-literature

Bimetallic reductive elimination from dinuclear Pd(III) complexes.

Project description:In 2009, we reported C-halogen reductive elimination reactions from dinuclear Pd(III) complexes and implicated dinuclear intermediates in Pd(OAc)(2)-catalyzed C-H oxidation chemistry. Herein, we report results of a thorough experimental and theoretical investigation of the mechanism of reductive elimination from such dinuclear Pd(III) complexes, which establish the role of each metal during reductive elimination. Our results implicate reductive elimination from a complex in which the dinuclear core is intact and suggest that redox synergy between the two metals is responsible for the facile reductive elimination reactions observed.

| S-EPMC2954233 | biostudies-literature

C(sp(3))-F reductive elimination from alkylgold(iii) fluoride complexes.

Project description:Rare examples of C(sp(3))-F reductive elimination were observed from several cis-F(2)Au(R)(IPr) intermediates generated by oxidation of (IPr)AuR complexes with XeF(2). For R groups bearing β-hydrogens, β-hydride elimination was competitive with C(sp(3))-F reductive elimination. For strained cyclic R groups and most acyclic R groups lacking β-hydrogens, carbocation-like rearrangements occurred prior to C(sp(3))-F reductive elimination. Kinetics of the decay of one cis-F(2)Au(R)(IPr) species, stereochemical analysis of reductive elimination with a chiral R group, and DFT analysis collectively suggest C(sp(3))-F reductive elimination proceeding through transient cationic [(IPr)Au(F)(R)](+) intermediates with significant ionization of the Au-alkyl bonds.

| S-EPMC3474378 | biostudies-literature

Anion-Dependent Switch in C-X Reductive Elimination Diastereoselectivity.

Project description:Reaction of a complex Pt organometallic species with electrophilic halogen sources in the presence of X- ligands changes the mechanism of reductive elimination from a concerted reductive coupling type to an SN2 type reductive elimination. In the absence of the added X- ligand the reductive elimination is stereoretentive; in its presence, the process is stereoinvertive. This selectivity hinges on the reactivity of a key five-coordinate Pt(IV) intermediate with the X- ligand.

| S-EPMC4157736 | biostudies-literature

Photoinitiated oxidative addition of CF3I to gold(I) and facile aryl-CF3 reductive elimination.

Project description:Herein we report the mechanism of oxidative addition of CF3I to Au(I), and remarkably fast Caryl-CF3 bond reductive elimination from Au(III) cations. CF3I undergoes a fast, formal oxidative addition to R3PAuR' (R = Cy, R' = 3,5-F2-C6H4, 4-F-C6H4, C6H5, 4-Me-C6H4, 4-MeO-C6H4, Me; R = Ph, R' = 4-F-C6H4, 4-Me-C6H4). When R' = aryl, complexes of the type R3PAu(aryl)(CF3)I can be isolated and characterized. Mechanistic studies suggest that near-ultraviolet light (?max = 313 nm) photoinitiates a radical chain reaction by exciting CF3I. Complexes supported by PPh3 undergo reversible phosphine dissociation at 110 °C to generate a three-coordinate intermediate that undergoes slow reductive elimination. These processes are quantitative and heavily favor Caryl-I reductive elimination over Caryl-CF3 reductive elimination. Silver-mediated halide abstraction from all complexes of the type R3PAu(aryl)(CF3)I results in quantitative formation of Ar-CF3 in less than 1 min at temperatures as low as -10 °C.

| S-EPMC4046758 | biostudies-literature

Interplay of water and a supramolecular capsule for catalysis of reductive elimination reaction from gold.

Project description:Supramolecular assemblies have gained tremendous attention due to their ability to catalyze reactions with the efficiencies of natural enzymes. Using ab initio molecular dynamics, we identify the origin of the catalysis by the supramolecular capsule Ga4L612- on the reductive elimination reaction from gold complexes and assess their similarity to natural enzymes. By comparing the free energies of the reactants and transition states for the catalyzed and uncatalyzed reactions, we determine that an encapsulated water molecule generates electric fields that contributes the most to the reduction in the activation free energy. Although this is unlike the biomimetic scenario of catalysis through direct host-guest interactions, the electric fields from the nanocage also supports the transition state to complete the reductive elimination reaction with greater catalytic efficiency. However it is also shown that the nanocage poorly organizes the interfacial water, which in turn creates electric fields that misalign with the breaking bonds of the substrate, thus identifying new opportunities for catalytic design improvements in nanocage assemblies.

| S-EPMC6972886 | biostudies-literature

Lewis acid-assisted Ir(iii) reductive elimination enables construction of seven-membered-ring sulfoxides.

Project description:Iridium has played an important role in the evolution of C-H activation chemistry over the last half century owing to its high reactivity towards stoichiometric C-H bond cleavage; however, the use of Ir(iii) complexes in catalytic C-H functionalization/C-C bond formation appears to have fallen off significantly. The main problem lies in the reductive elimination step, as iridium has a tendency to form stable and catalytically inactive Ir(iii) species. Herein, with a rationally designed Lewis acid assisted oxidatively induced strategy, the sluggish Ir(iii) reductive elimination is successfully facilitated, enabling the facile C-C bond formation. The X-ray crystal structure of a silver salt adduct of iridacycle and DFT calculations demonstrate that the sulfoxide group acts as a key bridge connecting the Ir(iii) metal centre with the silver Lewis acid, which facilitates the reductive elimination of the Ir(iii) metallacycle. Further identification of oxidants was carried out by performing stoichiometric reactions, which enables the development of catalytic construction of various highly functionalized seven-membered-ring sulfoxides, that are of great interest in medicinal chemistry and materials science.

| S-EPMC8162422 | biostudies-literature

Concerted aryl-sulfur reductive elimination from PNP pincer-supported Co(iii) and subsequent Co(i)/Co(iii) comproportionation.

Project description:This report discloses a combined experimental and computational study aimed at understanding C-S reductive elimination from Co(iii) supported by a diarylamido/bis(phosphine) PNP pincer ligand. Divalent (PNP)Co-aryl complexes could be easily oxidized to five-coordinate Co(iii) derivatives, and anion metathesis provided five-coordinate (PNP)Co(Ar)(SAr') complexes of Co(iii). In contrast to their previously described (POCOP)Co(Ar)(SAr') analogs, but similarly to the (PNP)Rh(Ar)(SAr') and (POCOP)Rh(Ar)(SAr') analogs, (PNP)Co(Ar)(SAr') undergo C-S reductive elimination with the formation of the desired diarylsulfide product ArSAr'. DFT studies and experimental observations are consistent with a concerted process. However, in contrast to the Rh analogs, the immediate product of such reductive elimination, the unobserved Co(i) complex (PNP)Co, un-dergoes rapid comproportionation with the (PNP)Co(Ar)(SAr') starting material to give Co(ii) compounds (PNP)Co-Ar and (PNP)Co-SAr'.

| S-EPMC7480512 | biostudies-literature

Nickela-electrocatalyzed C-H Alkoxylation with Secondary Alcohols: Oxidation-Induced Reductive Elimination at Nickel(III).

Project description:Nickela-electrooxidative C-H alkoxylations with challenging secondary alcohols were accomplished in a fully dehydrogenative fashion, thereby avoiding stoichiometric chemical oxidants, with H2 as the only stoichiometric byproduct. The nickela-electrocatalyzed oxygenation proved viable with various (hetero)arenes, including naturally occurring secondary alcohols, without racemization. Detailed mechanistic investigation, including DFT calculations and cyclovoltammetric studies of a well-defined C-H activated nickel(III) intermediate, suggest an oxidation-induced reductive elimination at nickel(III).

| S-EPMC7028089 | biostudies-literature

Unexpected C(carbene)-X (X: I, Br, Cl) Reductive Elimination From N-Heterocyclic Carbene Copper Halide Complexes Under Oxidative Conditions.

Project description:The non-innocent behaviors of NHC ligands have attracted wide attention due to their important implications for catalyst designs and reaction mechanisms. Herein, we report facile C(carbene)-halogen reductive eliminations from NHC copper halide complexes at RT under oxidative conditions. Density functional calculations on a simplified model system suggest that the reactions occur through oxidation of Cu(I) to Cu(III) species followed by C(carbene)-halogen reductive eliminations from NHC Cu(III) halide complexes. Remarkably short C(carbene)-chloride contacts and rare interactions between the chloride lone pair electrons and the C(carbene)p(π) orbital were found for the calculated NHC Cu(III) chlorides. The facile C(carbene)-X reductive elimination reported here warrants consideration as a potential decomposition pathway in reactions involving NHC-supported high-valent metal complexes, especially with late transition metals.

| S-EPMC2992331 | 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