Browse
Submit Data
Databases
API
Help

Dataset Information

38 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Iridium-Catalyzed α-Selective Arylation of Styrenes by Dual C-H Functionalization.

ABSTRACT: An Ir^I -system modified with a ferrocene derived bisphosphine ligand promotes α-selective arylation of styrenes by dual C-H functionalization. These studies offer a regioisomeric alternative to the Pd-catalyzed Fujiwara-Moritani reaction.

SUBMITTER: Cooper P

PROVIDER: S-EPMC6391973 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Iridium-catalyzed α-selective deuteration of alcohols.

Project description:The development of chemoselective C(sp3)-H deuteration is of particular interest in synthetic chemistry. We herein report the α-selective, iridium(iii)-bipyridonate-catalyzed hydrogen(H)/deuterium(D) isotope exchange of alcohols using deuterium oxide (D2O) as the primary deuterium source. This method enables the direct, chemoselective deuteration of primary and secondary alcohols under basic or neutral conditions without being affected by coordinative functional groups such as imidazole and tetrazole. Successful substrates for deuterium labelling include the pharmaceuticals losartan potassium, rapidosept, guaifenesin, and diprophylline. The deuterated losartan potassium shows higher stability towards the metabolism by CYP2C9 than the protiated analogue. Kinetic and DFT studies indicate that the direct deuteration proceeds through dehydrogenation of alcohol to the carbonyl intermediate, conversion of [IrIII-H] to [IrIII-D] with D2O, and deuteration of the carbonyl intermediate to give the α-deuterated product.

| S-EPMC9350590 | biostudies-literature

Enantioselective total syntheses of (-)-taiwaniaquinone H and (-)-taiwaniaquinol B by iridium-catalyzed borylation and palladium-catalyzed asymmetric α-arylation.

Project description:We report a concise, enantioselective total synthesis of (-)-taiwaniaquinone H and the first enantioselective total synthesis of (-)-taiwaniaquinol B by a route that includes asymmetric palladium-catalyzed α-arylation of a ketone with an aryl bromide that was generated by sterically controlled halogenation via iridium-catalyzed C-H borylation. This asymmetric α-arylation creates the benzylic quaternary stereogenic center present in the taiwaniaquinoids. The synthesis was completed efficiently by developing a Lewis acid-promoted cascade to construct the [6,5,6] tricyclic core of an intermediate common to the synthesis of a number of taiwaniaquinoids. Through the preparation of these compounds, we demonstrate the utility of constructing benzylic quaternary stereogenic centers, even those lacking a carbonyl group in the α-position, by asymmetric α-arylation.

| S-EPMC3042318 | biostudies-literature

Highly Diastereoselective Functionalization of Piperidines by Photoredox-Catalyzed α-Amino C-H Arylation and Epimerization.

Project description:We report a photoredox-catalyzed α-amino C-H arylation reaction of highly substituted piperidine derivatives with electron-deficient cyano(hetero)arenes. The scope and limitations of the reaction were explored, with piperidines bearing multiple substitution patterns providing the arylated products in good yields and with high diastereoselectivity. To probe the mechanism of the overall transformation, optical and fluorescent spectroscopic methods were used to investigate the reaction. By employing flash-quench transient absorption spectroscopy, we were able to observe electron transfer processes associated with radical formation beyond the initial excited-state Ir(ppy)3 oxidation. Following the rapid and unselective C-H arylation reaction, a slower epimerization occurs to provide the high diastereomer ratio observed for a majority of the products. Several stereoisomerically pure products were resubjected to the reaction conditions, each of which converged to the experimentally observed diastereomer ratios. The observed distribution of diastereomers corresponds to a thermodynamic ratio of isomers based upon their calculated relative energies using density functional theory (DFT).

| S-EPMC7318553 | biostudies-literature

Selective Dealkenylative Functionalization of Styrenes via C-C Bond Cleavage.

Project description:As a readily available feedstock, styrene with about 25 million tons of global annual production serves as an important building block and organic synthon for the synthesis of fine chemicals, polystyrene plastics, and elastomers. Thus, in the past decades, many direct transformations of this costless styrene feedstock were disclosed for the preparation of high-value chemicals, which to date, generally performed on the functionalization of styrenes through the allylic C-H bond, C(sp2 )-H bond, or the C=C double bond cleavage. However, the dealkenylative functionalization of styrenes via the direct C-C single bond cleavage is so far challenging and still unknown. Herein, we report the novel and efficient C-C amination and hydroxylation reactions of styrenes for the synthesis of valuable aryl amines and phenols via the site-selective C(Ar)-C(alkenyl) single bond cleavage. This chemistry unlocks the new transformation and application of the styrene feedstock and provides an efficient protocol for the late-stage modification of substituted styrenes with the site-directed dealkenylative amination and hydroxylation.

| S-EPMC7676249 | biostudies-literature

Twofold C-H functionalization: palladium-catalyzed ortho arylation of anilides.

Project description:The ortho arylation of anilides to form biphenyls via a twofold C-H functionalization/C-C bond-forming process is described. The oxidative coupling takes place in the presence of 5-10 mol % of Pd(OAc)2, 10-20 mol % of DMSO, and 4-11 equiv of the aryl substrate in TFA under an oxygen atmosphere. No metal-containing cocatalyst is required.

| S-EPMC2489205 | biostudies-literature

Synthesis of α-Arylphosphonates Using Copper-Catalyzed α-Arylation and Deacylative α-Arylation of β-Ketophosphonates.

Project description:Efficient methods for the direct arylation and deacylative arylation of β-ketophosphonates with iodoarenes in presence of a copper(I) or a copper(II) salt as the catalysts were developed. The corresponding α-arylphosphonates were obtained in high yields. A tentative mechanism for the deacylative arylation reaction was proposed on the basis of the experimental data.

| S-EPMC3324819 | biostudies-literature

Pd-catalyzed α-arylation of trimethylsilyl enolates of α,α-difluoroacetamides.

Project description:We report the arylation and heteroarylation of α,α-difluoro-α-(trimethylsilyl)acetamides with aryl and heteroaryl bromides catalyzed by an air- and moisture-stable palladacyclic complex containing P(t-Bu)2Cy as ligand. A broad range of electronically varied aryl and heteroaryl bromides underwent this transformation to afford α-aryl-α,α-difluoroacetamides in high yields. Due to the electrophilicity of the fluorinated amide, this palladium-catalyzed cross-coupling reaction provides a versatile platform to generate a range of α,α-difluoro carbonyl compounds, such as α-aryl-α,α-difluoroketones, -acetaldehydes, -acetates, and acetic acids, and difluoroalkyl derivatives, such as 2-aryl-2,2-difluoroethanols and -ethylamines, under mild conditions.

| S-EPMC4210146 | biostudies-literature

Iridium-catalyzed selective 1,2-hydrosilylation of N-heterocycles.

Project description:A silylene-bridged Ir dimer in situ generated from [Ir(coe)2Cl]2 and Et2SiH2 was found to catalyze the hydrosilylation of N-heteroaromatics to furnish dearomatized azacyclic products with high activity (up to 1000 TONs), excellent selectivity, and good functional group tolerance. The substrate scope was highly broad, including (iso)quinolines, substituted pyridines, pyrimidines, pyrazines, deazapurines, triazines, and benzimidazoles. Mechanistic studies such as a kinetic profile, rate-order assessment, and investigation of the electronic substituent effects on the initial rates were performed to access the detailed pathways. One pathway is proposed to involve an intramolecular insertion of the C[double bond, length as m-dash]N moiety of the substrates into the Ir-H bond of a resting species to form an Ir-amido silyl intermediate, followed by reductive elimination. The synthetic utility was proven by successful application to cinchona alkaloids, and facile post-synthetic transformations of the 1,2-dihydroquinoline products.

| S-EPMC6020754 | biostudies-literature

Rhodium(III)-catalyzed arylation of Boc-imines via C-H bond functionalization.

Project description:The first rhodium-catalyzed arylation of imines proceeding via C-H bond functionalization is reported. Use of a non-coordinating halide abstractor is important to obtain reactivity. Aryl-branched N-Boc-amines are formed, and a wide range of functionality is compatible with the reaction.

| S-EPMC3045530 | biostudies-literature

Site-Selective Functionalization of (sp<sup>3</sup> )C-H Bonds Catalyzed by Artificial Metalloenzymes Containing an Iridium-Porphyrin Cofactor.

Project description:The selective functionalization of one C-H bond over others in nearly identical steric and electronic environments can facilitate the construction of complex molecules. We report site-selective functionalizations of C-H bonds, differentiated solely by remote substituents, catalyzed by artificial metalloenzymes (ArMs) that are generated from the combination of an evolvable P450 scaffold and an iridium-porphyrin cofactor. The generated systems catalyze the insertion of carbenes into the C-H bonds of a range of phthalan derivatives containing substituents that render the two methylene positions in each phthalan inequivalent. These reactions occur with site-selectivity ratios of up to 17.8:1 and, in most cases, with pairs of enzyme mutants that preferentially form each of the two constitutional isomers. This study demonstrates the potential of abiotic reactions catalyzed by metalloenzymes to functionalize C-H bonds with site selectivity that is difficult to achieve with small-molecule catalysts.

| S-EPMC6759379 | 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