Browse
Submit Data
Databases
API
Help

Dataset Information

37 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Recyclable Heterogeneous Chitosan Supported Copper Catalyst for Silyl Conjugate Addition to ?,?-Unsaturated Acceptors in Water.

ABSTRACT: The first example of an environmentally-benign chitosan supported copper catalyzed conjugate silylation of ?,?-unsaturated acceptors was accomplished in water under mild conditions. This protocol provides an efficient pathway to achieve an important class of ?-silyl carbonyl compounds and the desired products were obtained in good to excellent yields. Gram-scale synthesis and easy transformation of obtained ?-silyl products were also been demonstrated. Remarkably, this chitosan supported copper catalyst can be easily recycled and reused six times without any significant decrease of catalytic activity. The advantages of this newly developed method include operational simplicity, good functional group tolerance, scale-up ability, ready availability, and easy recyclability of catalyst.

SUBMITTER: Zhu L

PROVIDER: S-EPMC6415219 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Recyclable Heterogeneous Chitosan Supported Copper Catalyst for Silyl Conjugate Addition to α,β-Unsaturated Acceptors in Water.

Zhu Lei L Li Bojie B Wang Shan S Wang Wei W Wang Liansheng L Ding Liang L Qin Caiqin C

Polymers 20180401 4

The first example of an environmentally-benign chitosan supported copper catalyzed conjugate silylation of α,β-unsaturated acceptors was accomplished in water under mild conditions. This protocol provides an efficient pathway to achieve an important class of β-silyl carbonyl compounds and the desired products were obtained in good to excellent yields. Gram-scale synthesis and easy transformation of obtained β-silyl products were also been demonstrated. Remarkably, this chitosan supported copper ...[more]

PMID: 30966420

Similar Datasets

Borylation of α,β-Unsaturated Acceptors by Chitosan Composite Film Supported Copper Nanoparticles.

Project description:We describe here the preparation of copper nanoparticles stabilized on a chitosan/poly (vinyl alcohol) composite film. This material could catalyze the borylation of α,β-unsaturated acceptors in aqueous media under mild conditions. The corresponding organoboron compounds as well as their converted β-hydroxyl products were all obtained in good to excellent yields. It is noteworthy that this catalyst of copper nanoparticles can be easily recycled eight times and remained catalytically reactive. This newly developed methodology provides an efficient and sustainable pathway for the synthesis of organoboron compounds and application of copper nanoparticles.

| S-EPMC5977340 | biostudies-literature

Palladium Supported on Porous Organic Polymer as Heterogeneous and Recyclable Catalyst for Cross Coupling Reaction.

Project description:Palladium immobilized on an amide and ether functionalized porous organic polymer (Pd@AEPOP) is reported to be an effective heterogeneous catalyst for the Heck cross-coupling reaction of aryl iodides with styrene for the synthesis of diphenylethene derivatives. Excellent yields can be obtained using a 0.8 mol% Pd catalyst loading under the optimized reaction condition. The heterogeneous Pd@AEPOP catalyst can also be applied on the Suzuki reaction and the reduction of nitroarene.

| S-EPMC9332046 | biostudies-literature

A homogeneous, recyclable rhodium(I) catalyst for the hydroarylation of Michael acceptors.

Project description:A robust and practical polymer-supported, recyclable biphephos rhodium(I) catalyst has been developed. Control of polymer molecular weight allowed the tuning of solubility such that the polymer-supported catalyst is soluble in nonpolar solvents and not soluble in polar solvents. Thus, catalytic addition of aryl- and vinylboronic acids to enones occurs under completely homogeneous conditions and catalyst recycle can be achieved by simple precipitation and filtration.

| S-EPMC2739661 | biostudies-literature

Textile-supported silver nanoparticles as a highly efficient and recyclable heterogeneous catalyst for nitroaromatic reduction at room temperature.

Project description:A novel textile-based nanosilver catalyst was prepared with a facile synthetic method. The textile-supported nanosilver (TsNS) proved to be an excellent heterogeneous catalyst for the reduction of nitroaromatics with a broad substrate scope. It can be recycled for up to 6 times without significantly compromising its catalytic efficacy. The TsNS catalyst was developed into a column reactor, demonstrating its practical application with the advantages of low cost, ease of operation and large scale synthesis capabilities. Scanning electron microscopy (SEM) showed that there were few changes to the catalyst's surface after the reaction. Besides, inductively coupled plasma (ICP) analysis showed that few silver particles leaked, and the interactions between the nitro groups of the nitroaromatics and the nanosilver particles were characterized by X-ray photoelectron spectroscopy (XPS), which lead to the proposal of a four-step mechanism for the reduction reaction.

| S-EPMC9078239 | biostudies-literature

Catalyst-Free Formal Conjugate Addition/Aldol or Mannich Multicomponent Reactions of Mixed Aliphatic Organozinc Reagents, π-Electrophiles and Michael Acceptors.

Project description:Catalyst-free multicomponent reactions of mixed alkylzinc reagents with Michael acceptors and aldehydes, ketones or activated imines are described. Primary, secondary and tertiary alkylzinc reagents, pre-generated in acetonitrile from the corresponding iodoalkanes, were used in the process, leading to the very efficient formation of a variety of β-hydroxycarbonyl compounds. The imines showed more contrasting results, due to the direct addition of the organozinc compound to the C=N bond. Mechanistic assays involving TEMPO account for a polar instead of a radical character of the reaction.

| S-EPMC9919058 | biostudies-literature

Palladium-catalyzed asymmetric conjugate addition of arylboronic acids to heterocyclic acceptors.

Project description:Flava Flavanone: Asymmetric conjugate additions to chromones and 4-quinolones are reported utilizing a single catalyst system formed in situ from Pd(OCOCF(3))(2) and (S)-tBuPyOX. Notably, these reactions are performed in wet solvent under ambient atmosphere, and employ readily available arylboronic acids as the nucleophile, thus providing ready access to these asymmetric heterocycles (see scheme).

| S-EPMC3753812 | biostudies-literature

Pd-catalyzed carbonylative conjugate addition of dialkylzinc reagents to unsaturated carbonyls.

Project description:The Pd-catalyzed addition of organozinc reagents to unsaturated carbonyls in the presence of carbon monoxide provides 1,4-diketones in good yield. The reaction was studied with a number of substituted cyclic and acyclic ketones as well as alpha,beta-unsaturated aldehydes.

| S-EPMC2929296 | biostudies-literature

Glycolysis of Poly(Ethylene Terephthalate) Using Biomass-Waste Derived Recyclable Heterogeneous Catalyst.

Project description:Plastic production has increased by almost 200-fold annually from 2 million metric tons per year in 1950s to 359 million metric tons in 2018. With this rapidly increasing production, plastic pollution has become one of the most demanding environmental issues and tremendous efforts have been initiated by the research community for its disposal. In this present study, we reported for the first time, a biomass-waste-derived heterogeneous catalyst prepared from waste orange peel for the depolymerisation of poly(ethylene terephthalate) (PET) to its monomer, bis(2-hydroxyethyl terephthalate) (BHET). The prepared orange peel ash (OPA) catalyst was well-characterised using techniques such as IR, inductively coupled plasma (ICP)-OES (Optical Emission Spectrometry), XRD, X-ray fluorescence (XRF), SEM, energy-dispersive X-ray spectroscopy (EDX), TEM, BET (Brunauer-Emmett-Teller) and TGA. The catalyst was found to be composed of basic sites, high surface area, and a notable type-IV N2 adsorption-desorption isotherm indicating the mesoporous nature of the catalyst, which might have eventually enhanced the rate of the reaction as well as the yield of the product. The catalyst completely depolymerises PET within 90 min, producing 79% of recrystallised BHET. The ability of reusing the catalysts for 5 consecutive runs without significant depreciation in the catalytic activity and its eco- and environmental-friendliness endorses this protocol as a greener route for PET recycling.

| S-EPMC7794874 | biostudies-literature

Exceptionally Efficient and Recyclable Heterogeneous Metal-Organic Framework Catalyst for Glucose Isomerization in Water.

Project description:Heterogeneous catalysts are desired for the conversion of glucose, the most abundant sugar in renewable biomass, but presently their synthesis requires highly toxic chemicals with long synthesis times. We report the conversion of glucose into fructose and 5-hydroxymethylfurfural on a heterogeneous catalyst that is stable and selective and operates in the most environmentally benign solvent, water. We used a bifunctional solid with Lewis and Brønsted acid sites by partially replacing the organic linker of the zirconium organic framework UiO-66 with 2-monosulfo-benzene-1,4-dicarboxylate. This catalyst showed high product selectivity (90?%) to 5-hydroxymethylfurfural and fructose at 140?°C in water after a reaction time of 3?h. It was recyclable and showed only a minor loss in activity after the third recycle, offering a realistic solution for the bottleneck glucose isomerization reaction for scale-up and industrial application of biomass utilization.

| S-EPMC5838531 | biostudies-literature

Synthesis of Unsaturated Silyl Heterocycles via an Intramolecular Silyl-Heck Reaction.

Project description:We report the synthesis of unsaturated silacycles via an intramolecular silyl-Heck reaction. Using palladium catalysis, silicon electrophiles tethered to alkenes cyclize to form 5- and 6-membered silicon heterocycles. The effects of alkene substitution and tether length on the efficiency and regioselectivity of the cyclizations are described. Finally, through the use of an intramolecular tether, the first examples of disubstituted alkenes in silyl-Heck reactions are reported.

| S-EPMC7236810 | 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