Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Hydroperoxidations of Alkenes using Cobalt Picolinate Catalysts.

ABSTRACT: Hydroperoxides were synthesized in one step from various alkenes using Co(pic)₂ as the catalyst with molecular oxygen and tetramethyldisiloxane (TMDSO). The hydration product could be obtained using a modified catalyst, Co(3-mepic)₂, with molecular oxygen and phenylsilane. Formation of hydroperoxides occurred through a rapid Co-O bond metathesis of a peroxycobalt compound with isopropanol.

SUBMITTER: Peralta-Neel Z

PROVIDER: S-EPMC9022486 | biostudies-literature | 2021 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Hydroperoxidations of Alkenes using Cobalt Picolinate Catalysts.

Peralta-Neel Zulema Z Woerpel K A KA

Organic letters 20210614 13

Hydroperoxides were synthesized in one step from various alkenes using Co(pic)2 as the catalyst with molecular oxygen and tetramethyldisiloxane (TMDSO). The hydration product could be obtained using a modified catalyst, Co(3-mepic)2, with molecular oxygen and phenylsilane. Formation of hydroperoxides occurred through a rapid Co-O bond metathesis of a peroxycobalt compound with isopropanol. ...[more]

PMID: 34125543

Similar Datasets

Cobalt-based Catalysts for Ammonia Decomposition.

Project description:An effect of promoters such as calcium, aluminium, and potassium oxides and also addition of chromium and manganese on the structure of cobalt catalysts was examined. Studies of the catalytic ammonia decomposition over the cobalt catalysts are presented. The studies of the ammonia decomposition were carried out for various ammonia-hydrogen mixtures in which ammonia concentration varied in the range from 10% to 100%. Co(0) catalyst, promoted by oxides of aluminium, calcium, and potassium, showed the highest activity in the ammonia decomposition reaction. Contrary to expectations, it was found that chromium and manganese addition into the catalysts decreased their activity.

| S-EPMC5458937 | biostudies-other

Control of Selectivity through Synergy between Catalysts, Silanes and Reaction Conditions in Cobalt-Catalyzed Hydrosilylation of Dienes and Terminal Alkenes.

Project description:Readily accessible ( i-PrPDI)CoCl2 [ i-Pr PDI = 2,6-bis(2,6-diisopropylphenyliminoethyl)pyridine] reacts with 2 equivalents of NaEt3BH at -78 °C in toluene to generate a catalyst that effects highly selective anti-Markovnikov hydrosilylation of the terminal double bond in 1,3- and 1,4-dienes. Primary and secondary silanes such as PhSiH3, Ph2SiH2 and PhSi(Me)H2 react with a broad spectrum of terminal dienes without affecting the configuration of the other double bond. When dienes conjugated to an aromatic ring are involved, both Markovnikov and anti-Markovnikov products are formed. The reaction is tolerant of various functional groups such as an aryl bromide, aryl iodide, protected alcohol, and even a silyl enol ether. Reactions of 1-alkene under similar conditions cleanly lead to a mixture of Markovnikov and anti-Markovnikov hydrosilation products, where ratio of the products increasingly favors the latter, as the size of the 2,6-substituents in the iminoylaryl group becomes larger. The complex ( i-PrPDI)CoCl2 gives exclusively the linear silane for a wide variety of terminal alkenes. Mechanistic studies suggest a pathway that involves a key role for an in situ generated metal hydride, (L)Co(I)-H. Exclusive reduction of the terminal double bond (vis-a-vis hydrosilylation) when (EtO)2Si(Me)H is used in the place of PhSiH3 is explained on the basis of an alternate silane-mediated decomposition path for the linear Co(I)-alkyl intermediate.

| S-EPMC5459319 | biostudies-literature

Latent ruthenium-indenylidene catalysts bearing a N-heterocyclic carbene and a bidentate picolinate ligand.

Project description:A silver-free methodology was developed for the synthesis of unprecedented N-heterocyclic carbene ruthenium indenylidene complexes bearing a bidentate picolinate ligand. The highly stable (SIPr)(picolinate)RuCl(indenylidene) complex 4a (SIPr = 1,3-bis(2-6-diisopropylphenyl)imidazolidin-2-ylidene) demonstrated excellent latent behaviour in ring closing metathesis (RCM) reaction and could be activated in the presence of a Brønsted acid. The versatility of the catalyst 4a was subsequently demonstrated in RCM, cross-metathesis (CM) and enyne metathesis reactions.

| S-EPMC4578404 | biostudies-literature

Organozinc pivalates for cobalt-catalyzed difluoroalkylarylation of alkenes.

Project description:Installation of fluorine into pharmaceutically relevant molecules plays a vital role in their properties of biology or medicinal chemistry. Direct difunctionalization of alkenes and 1,3-dienes to achieve fluorinated compounds through transition-metal catalysis is challenging, due to the facile β-H elimination from the Csp3‒[M] intermediate. Here we report a cobalt-catalyzed regioselective difluoroalkylarylation of both activated and unactivated alkenes with solid arylzinc pivalates and difluoroalkyl bromides through a cascade Csp3‒Csp3/Csp3‒Csp2 bond formation under mild reaction conditions. Indeed, a wide range of functional groups on difluoroalkyl bromides, olefins, 1,3-dienes as well as (hetero)arylzinc pivalates are well tolerated by the cobalt-catalyst, thus furnishing three-component coupling products in good yields and with high regio- and diastereoselectivity. Kinetic experiments comparing arylzinc pivalates and conventional arylzinc halides highlight the unique reactivity of these organozinc pivalates. Mechanistic studies strongly support that the reaction involves direct halogen atom abstraction via single electron transfer to difluoroalkyl bromides from the in situ formed cobalt(I) species, thus realizing a Co(I)/Co(II)/Co(III) catalytic cycle.

| S-EPMC8285467 | 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

Electrocatalytic H2 evolution using binuclear cobalt complexes as catalysts.

Project description:We report herein on the use of two binuclear cobalt complexes with the N,N'-bis(salicylidene)-phenylmethanediamine ligand as catalysts for the H2 evolution in DMF solution with acetic acid as proton source. Both experimental analyses (electrochemical analysis, spectroscopy analysis) and theoretical analysis (foot-of-the wave analysis) were employed. These catalysts required an overpotential of ca. 470 mV to catalyze the H2 evolution and generated H2 gas with a faradaic efficiency of 85-95% as calculated on the basis of after 5 hour bulk electrolysis. The kinetic investigation showed the maximal TOF value of 50 s-1 on the basis of an ECEC mechanism. Two cobalt centers, standing at a long distance of 4.175 Å, operated independently during catalysis without a synergetic effect or cooperation capability.

| S-EPMC9479770 | biostudies-literature

Highly active and efficient catalysts for alkoxycarbonylation of alkenes.

Project description:Carbonylation reactions of alkenes constitute the most important industrial processes in homogeneous catalysis. Despite the tremendous progress in this transformation, the development of advanced catalyst systems to improve their activity and widen the range of feedstocks continues to be essential for new practical applications. Herein a palladium catalyst based on 1,2-bis((tert-butyl(pyridin-2-yl)phosphanyl)methyl)benzene L3 (pytbpx) is rationally designed and synthesized. Application of this system allows a general alkoxycarbonylation of sterically hindered and demanding olefins including all kinds of tetra-, tri- and 1,1-disubstituted alkenes as well as natural products and pharmaceuticals to the desired esters in excellent yield. Industrially relevant bulk ethylene is functionalized with high activity (TON: >1,425,000; TOF: 44,000 h-1 for initial 18 h) and selectivity (>99%). Given its generality and efficiency, we expect this catalytic system to immediately impact both the chemical industry and research laboratories by providing a practical synthetic tool for the transformation of nearly any alkene into a versatile ester product.

| S-EPMC5288498 | biostudies-literature

Characteristics of polyaniline cobalt supported catalysts for epoxidation reactions.

Project description:A study of polyaniline (PANI) doping with various cobalt compounds, that is, cobalt(II) chloride, cobalt(II) acetate, and cobalt(II) salen, is presented. The catalysts were prepared by depositing cobalt compounds onto the polymer surface. PANI powders containing cobalt ions were obtained by one- or two-step method suspending PANI in the following acetonitrile/acetic acid solution or acetonitrile and then acetic acid solution. Moreover different ratios of Co(II) : PANI were studied. Catalysts obtained with both methods and at all ratios were investigated using various techniques including AAS and XPS spectroscopy. The optimum conditions for preparation of PANI/Co catalysts were established. Catalytic activity of polyaniline cobalt(II) supported catalysts was tested in dec-1-ene epoxidation with molecular oxygen at room temperature. The relationship between the amount of cobalt species, measured with both AAS and XPS techniques, and the activity of PANI-Co catalysts has been established.

| S-EPMC3948595 | biostudies-other

Controllable Isomerization of Alkenes by Dual Visible-Light-Cobalt Catalysis.

Project description:We report herein that thermodynamic and kinetic isomerization of alkenes can be accomplished by the combination of visible light with Co catalysis. Utilizing Xantphos as the ligand, the most stable isomers are obtained, while isomerizing terminal alkenes over one position can be selectively controlled by using DPEphos as the ligand. The presence of the donor-acceptor dye 4CzIPN accelerates the reaction further. Transformation of exocyclic alkenes into the corresponding endocyclic products could be efficiently realized by using 4CzIPN and Co(acac)2 in the absence of any additional ligands. Spectroscopic and spectroelectrochemical investigations indicate CoI being involved in the generation of a Co hydride, which subsequently adds to alkenes initiating the isomerization.

| S-EPMC6519376 | biostudies-literature

Activity enhancement of cobalt catalysts by tuning metal-support interactions.

Project description:Interactions between metal nanoparticles and support materials can strongly influence the performance of catalysts. In particular, reducible oxidic supports can form suboxides that can decorate metal nanoparticles and enhance catalytic performance or block active sites. Therefore, tuning this metal-support interaction is essential for catalyst design. Here, we investigate reduction-oxidation-reduction (ROR) treatments as a method to affect metal-support interactions and related catalytic performance. Controlled oxidation of pre-reduced cobalt on reducible (TiO2 and Nb2O5) and irreducible (?-Al2O3) supports leads to the formation of hollow cobalt oxide particles. The second reduction results in a twofold increase in cobalt surface area only on reducible oxides and proportionally enhances the cobalt-based catalytic activity during Fischer-Tropsch synthesis at industrially relevant conditions. Such activities are usually only obtained by noble metal promotion of cobalt catalysts. ROR proves an effective approach to tune the interaction between metallic nanoparticles and reducible oxidic supports, leading to improved catalytic performance.

| S-EPMC6203836 | biostudies-other

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