Browse
Submit Data
Databases
API
Help

Dataset Information

18 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Cobalt-catalyzed methoxycarbonylation of substituted dichlorobenzenes as an example of a facile radical anion nucleophilic substitution in chloroarenes.

ABSTRACT: A thorough mechanistic study on cobalt-catalysed direct methoxycarbonylation reactions of chlorobenzenes in the presence of methyl oxirane on a wide range of substrates, including poly- and monochloro derivatives with multiple substituents, is reported. The results demonstrate that the reaction is potentially useful as it proceeds under very mild conditions (t = 62 °C, PCO = 1 bar) and converts aryl chlorides to far more valuable products (especially ortho-substituted benzoic acids and esters) in high yields. This transformation also offers another opportunity for the utilization of environmentally harmful polychlorinated benzenes and biphenyls (PCBs). This study is the first to discover an unexpected universal positive ortho-effect: the proximity of any substituent (including Me, Ph, and MeO groups and halogen atoms) to the reaction centre accelerates the methoxycarbonylation in chlorobenzenes. The effect of the ortho-substituents is discussed in detail and explained in terms of a radical anion reaction mechanism. The advantages of the methoxycarbonylation as a model for the mechanistic study of radical anion reactions are also illustrated.

SUBMITTER: Khaibulova TS

PROVIDER: S-EPMC6270984 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

A Persistent Phosphanyl-Substituted Thioketyl Radical Anion.

Project description:Alkali metal salts, M+ [Ter(iPr)P-C(=S)-P(iPr)2 S].- (M=Na, K; 2_M; Ter=2,6-bis-(2,4,6-trimethylphenyl)phenyl) containing a room-temperature-stable thioketyl radical anion were obtained by reduction of the thioketone precursor, Ter(iPr)P-C(=S)-P(iPr)2 S (1), with alkali metals (Na, K). Single-crystal X-ray studies as well as EPR spectroscopy revealed the unequivocal existence of a thioketyl radical anion in the solid state and in solution, respectively. The computed Mulliken spin density within 2_M is mainly located at the sulfur (49 %) and the carbonyl carbon (33 %) atoms. Upon adding [2.2.2]-cryptand to the radical species 2_K to minimize the interionic interaction, an activation reaction was observed, yielding a potassium salt with a phosphanyl thioether based anion, [K(crypt)]+ [Ter(iPr)P-C(-S-iPr)-P(iPr)2 S]- (3) as the product of an intermolecular shift of an iPr group from a second anion. The products were fully characterized and application of the radical anion as a reducing agent was demonstrated.

| S-EPMC9303638 | biostudies-literature

Cation Radical-Accelerated Nucleophilic Aromatic Substitution for Amination of Alkoxyarenes.

Project description:Nucleophilic aromatic substitution (SNAr) is a common method for arene functionalization; however, reactions of this type are typically limited to electron-deficient aromatic halides. Herein, we describe a mild, metal-free, cation-radical accelerated nucleophilic aromatic substitution (CRA-SNAr) using a potent, highly oxidizing acridinium photoredox catalyst. Selective substitution of arene C-O bonds on a wide array of aryl ether substrates was shown with a variety of primary amine nucleophiles. Mechanistic evidence is also presented that supports the proposed CRA-SNAr pathway.

| S-EPMC7476680 | biostudies-literature

Photo-Initiated Cobalt-Catalyzed Radical Olefin Hydrogenation.

Project description:Outer-sphere radical hydrogenation of olefins proceeds via stepwise hydrogen atom transfer (HAT) from transition metal hydride species to the substrate. Typical catalysts exhibit M-H bonds that are either too weak to efficiently activate H2 or too strong to reduce unactivated olefins. This contribution evaluates an alternative approach, that starts from a square-planar cobalt(II) hydride complex. Photoactivation results in Co-H bond homolysis. The three-coordinate cobalt(I) photoproduct binds H2 to give a dihydrogen complex, which is a strong hydrogen atom donor, enabling the stepwise hydrogenation of both styrenes and unactivated aliphatic olefins with H2 via HAT.

| S-EPMC9292329 | biostudies-literature

FluoroFusion: NHC-Catalyzed Nucleophilic Aromatic Substitution Reaction Unveils Functional Perfluorinated Diarylmethanones.

Project description:A mild, facile, and metal-free approach via the N-heterocyclic carbene-catalyzed SNAr reaction between aryl aldehydes with perfluoroarenes to obtain the coveted functional perfluorinated diarylmethanones is disclosed. This method accommodates a diverse substrate range and exhibits notable tolerance toward various functional groups. Our success in modifying biologically relevant molecules, crafting a fully fluorinated bioisosteric analogue of drug candidate D1, and highlighting the potential of these ketones as valuable electrolyte additives for lithium-ion batteries (LIBs) underscores the versatility of our methodology.

| S-EPMC10964231 | biostudies-literature

Ligand-promoted cobalt-catalyzed radical hydroamination of alkenes.

Project description:Highly regio- and enantioselective intermolecular hydroamination of alkenes is a challenging process potentially leading to valuable chiral amines. Hydroamination of alkenes via metal-catalyzed hydrogen atom transfer (HAT) with good regioselectivity and functional group tolerance has been reported, however, high enantioselectivity has not been achieved due to the lack of suitable ligands. Here we report a ligand-promoted cobalt-catalyzed Markovnikov-type selective radical hydroamination of alkenes with diazo compounds. This operationally simple protocol uses unsymmetric NNN-tridentate (UNT) ligand, readily available alkenes and hydrosilanes to construct hydrazones with good functional group tolerance. The hydrazones can undergo nitrogen-nitrogen bond cleavage smoothly to deliver valuable amine derivatives. Additionally, asymmetric intermolecular hydroamination of unactivated aliphatic terminal alkenes using chiral N-imidazolinylphenyl 8-aminoquinoline (IPAQ) ligands has also been achieved to afford chiral amine derivatives with good enantioselectivities.

| S-EPMC7005876 | biostudies-literature

Efficient synthesis of 5-substituted 2-aryl-6-cyanoindolizines via nucleophilic substitution reactions.

Project description:2-Aryl-6-cyano-7-methyl-5-indolizinones were successfully converted into 2-aryl-5-chloro-6-cyano-7-methylindolizines. The obtained 5-chloroindolizines readily underwent nucleophilic substitution at position 5 leading in high yields to novel 5-functionalised indolizines.

| S-EPMC1399457 | biostudies-literature

The involvement of the trisulfur radical anion in electron-catalyzed sulfur insertion reactions: facile synthesis of benzothiazine derivatives under transition metal-free conditions.

Project description:An efficient and practical synthesis of benzothiazine by K2S initiated sulfur insertion reaction with enaminones via electron catalysis is developed. This protocol provides a new, environment-friendly and simple strategy to construct benzothiazine derivatives via formation of two C-S bonds under transition metal-free, additive-free and oxidant-free conditions. K2S not only provides the sulfur insertion source, but also ignites the reaction through the formation of a trisulfur radical anion and electrons in DMF.

| S-EPMC6013918 | biostudies-literature

Transition-Metal Catalysis of Nucleophilic Substitution Reactions: A Radical Alternative to SN1 and SN2 Processes.

Project description:Classical methods for achieving nucleophilic substitutions of alkyl electrophiles (SN1 and SN2) have limited scope and are not generally amenable to enantioselective variants that employ readily available racemic electrophiles. Radical-based pathways catalyzed by chiral transition-metal complexes provide an attractive approach to addressing these limitations.

| S-EPMC5532721 | biostudies-other

Nucleophilic addition and substitution at coordinatively saturated boron by facile 1,2-hydrogen shuttling onto a carbene donor.

Project description:The reaction of [(cAACMe)BH3] (cAACMe = 1-(2,6-iPr2C6H3)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) with a range of organolithium compounds led to the exclusive formation of the corresponding (dihydro)organoborates, Li+[(cAACMeH)BH2R]- (R = sp3-, sp2-, or sp-hybridised organic substituent), by migration of one boron-bound hydrogen atom to the adjacent carbene carbon of the cAAC ligand. A subsequent deprotonation/salt metathesis reaction with Me3SiCl or spontaneous LiH elimination yielded the neutral cAAC-supported mono(organo)boranes, [(cAACMe)BH2R]. Similarly the reaction of [(cAACMe)BH3] with a neutral donor base L resulted in adduct formation by shuttling one boron-bound hydrogen to the cAAC ligand, to generate [(cAACMeH)BH2L], either irreversibly (L = cAACMe) or reversibly (L = pyridine). Variable-temperature NMR data and DFT calculations on [(cAACMeH)BH2(cAACMe)] show that the hydrogen on the former carbene carbon atom exchanges rapidly with the boron-bound hydrides.

| S-EPMC5637459 | biostudies-literature

Structural basis for substrate selectivity and nucleophilic substitution mechanisms in human adenine phosphoribosyltransferase catalyzed reaction.

Project description:The reversible adenine phosphoribosyltransferase enzyme (APRT) is essential for purine homeostasis in prokaryotes and eukaryotes. In humans, APRT (hAPRT) is the only enzyme known to produce AMP in cells from dietary adenine. APRT can also process adenine analogs, which are involved in plant development or neuronal homeostasis. However, the molecular mechanism underlying substrate specificity of APRT and catalysis in both directions of the reaction remains poorly understood. Here we present the crystal structures of hAPRT complexed to three cellular nucleotide analogs (hypoxanthine, IMP, and GMP) that we compare with the phosphate-bound enzyme. We established that binding to hAPRT is substrate shape-specific in the forward reaction, whereas it is base-specific in the reverse reaction. Furthermore, a quantum mechanics/molecular mechanics (QM/MM) analysis suggests that the forward reaction is mainly a nucleophilic substitution of type 2 (SN2) with a mix of SN1-type molecular mechanism. Based on our structural analysis, a magnesium-assisted SN2-type mechanism would be involved in the reverse reaction. These results provide a framework for understanding the molecular mechanism and substrate discrimination in both directions by APRTs. This knowledge can play an instrumental role in the design of inhibitors, such as antiparasitic agents, or adenine-based substrates.

| S-EPMC6690681 | 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