Browse
Submit Data
Databases
API
Help

Dataset Information

16 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Elucidation of Diels-Alder Reaction Network of 2,5-Dimethylfuran and Ethylene on HY Zeolite Catalyst.

ABSTRACT: The reaction of 2,5-dimethylfuran and ethylene to produce p-xylene represents a potentially important route for the conversion of biomass to high-value organic chemicals. Current preparation methods suffer from low selectivity and produce a number of byproducts. Using modern separation and analytical techniques, the structure of many of the byproducts produced in this reaction when HY zeolite is employed as a catalyst has been identified. From these data, a detailed reaction network is proposed demonstrating that hydrolysis and electrophilic alkylation reactions compete with the desired Diels-Alder/dehydration sequence. This information will allow the rational identification of more selective catalysts and more selective reaction conditions.

SUBMITTER: Do PT

PROVIDER: S-EPMC3539728 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Elucidation of Diels-Alder Reaction Network of 2,5-Dimethylfuran and Ethylene on HY Zeolite Catalyst.

Do Phuong T M PT McAtee Jesse R JR Watson Donald A DA Lobo Raul F RF

ACS catalysis 20121212 1

The reaction of 2,5-dimethylfuran and ethylene to produce p-xylene represents a potentially important route for the conversion of biomass to high-value organic chemicals. Current preparation methods suffer from low selectivity and produce a number of byproducts. Using modern separation and analytical techniques, the structure of many of the byproducts produced in this reaction when HY zeolite is employed as a catalyst has been identified. From these data, a detailed reaction network is proposed ...[more]

PMID: 23316419

Similar Datasets

An Active Alkali-Exchanged Faujasite Catalyst for p-Xylene Production via the One-Pot Diels-Alder Cycloaddition/Dehydration Reaction of 2,5-Dimethylfuran with Ethylene.

Project description:The one-pot Diels-Alder cycloaddition (DAC)/dehydration (D) tandem reaction between 2,5-dimethylfuran and ethylene is a potent pathway toward biomass-derived p-xylene. In this work, we present a cheap and active low-silica potassium-exchanged faujasite (KY, Si/Al = 2.6) catalyst. Catalyst optimization was guided by a computational study of the DAC/D reaction mechanism over different alkali-exchanged faujasites using periodic density functional theory calculations complemented by microkinetic modeling. Two types of faujasite models were compared, i.e., a high-silica alkali-exchanged faujasite model representing isolated active cation sites and a low-silica alkali-exchanged faujasite in which the reaction involves several cations in the proximity. The mechanistic study points to a significant synergetic cooperative effect of the ensemble of cations in the faujasite supercage on the DAC/D reaction. Alignment of the reactants by their interactions with the cationic sites and stabilization of reaction intermediates contribute to the high catalytic performance. Experiments confirmed the prediction that KY is the most active catalyst among low-silica alkali-exchanged faujasites. This work is an example of how the catalytic reactivity of zeolites depends on multiple interactions between the zeolite and reagents.

| S-EPMC5805402 | biostudies-literature

Computational design of an enzyme catalyst for a stereoselective bimolecular Diels-Alder reaction.

Project description:The Diels-Alder reaction is a cornerstone in organic synthesis, forming two carbon-carbon bonds and up to four new stereogenic centers in one step. No naturally occurring enzymes have been shown to catalyze bimolecular Diels-Alder reactions. We describe the de novo computational design and experimental characterization of enzymes catalyzing a bimolecular Diels-Alder reaction with high stereoselectivity and substrate specificity. X-ray crystallography confirms that the structure matches the design for the most active of the enzymes, and binding site substitutions reprogram the substrate specificity. Designed stereoselective catalysts for carbon-carbon bond-forming reactions should be broadly useful in synthetic chemistry.

| S-EPMC3241958 | biostudies-literature

Chiral-at-Iron Catalyst for Highly Enantioselective and Diastereoselective Hetero-Diels-Alder Reaction.

Project description:This study demonstrates that chiral-at-iron complexes, in which all coordinated ligands are achiral and the overall chirality the consequence of a stereogenic iron center, are capable of catalyzing asymmetric transformations with very high enantioselectivities. The catalyst is based on a previously reported design (J. Am. Chem. Soc. 2017, 139, 4322), in which iron(II) is surrounded by two configurationally inert achiral bidentate N-(2-pyridyl)-substituted N-heterocyclic carbenes in a C2 -symmetric fashion and complemented by two labile acetonitriles. By replacing mesityl with more bulky 2,6-diisopropylphenyl substituents at the NHC ligands, the steric hindrance at the catalytic site was increased, thereby providing a markedly improved asymmetric induction. The new chiral-at-iron catalyst was applied to the inverse electron demand hetero-Diels-Alder reaction between β,γ-unsaturated α-ketoester and enol ethers provide 3,4-dihydro-2H-pyrans in high yields with excellent diastereoselectivities (up to 99 : 1 dr) and excellent enantioselectivities (up to 98 % ee). Other electron rich dienophiles are also suitable as demonstrated for a reaction with a vinyl azide.

| S-EPMC8251941 | biostudies-literature

Photochemical Hexadehydro-Diels-Alder Reaction.

Project description:We demonstrate that the hexadehydro-Diels-Alder (HDDA) cycloisomerization reaction to produce reactive benzyne derivatives can be initiated photochemically. As with the thermal variant of the HDDA process, the reactive intermediates are formed in the absence of reagents or the resulting byproducts required for the generation of benzynes by traditional methods. This photo-HDDA (or h?-HDDA) reaction occurs at much lower temperatures (including even at -70 °C) than the thermal HDDA, but the benzynes produced behave in the same fashion with respect to their trapping reactions, suggesting they are of the same electronic state.

| S-EPMC6348472 | biostudies-literature

The pentadehydro-Diels-Alder reaction.

Project description:In the classic Diels-Alder [4?+?2] cycloaddition reaction, the overall degree of unsaturation (or oxidation state) of the 4? (diene) and 2? (dienophile) pairs of reactants dictates the oxidation state of the newly formed six-membered carbocycle. For example, in the classic Diels-Alder reaction, butadiene and ethylene combine to produce cyclohexene. More recent developments include variants in which the number of hydrogen atoms in the reactant pair and in the resulting product is reduced by, for example, four in the tetradehydro-Diels-Alder (TDDA) and by six in the hexadehydro-Diels-Alder (HDDA) reactions. Any oxidation state higher than tetradehydro (that is, lacking more than four hydrogens) leads to the production of a reactive intermediate that is more highly oxidized than benzene. This increases the power of the overall process substantially, because trapping of the reactive intermediate can be used to increase the structural complexity of the final product in a controllable and versatile manner. Here we report an unprecedented overall 4??+?2? cycloaddition reaction that generates a different, highly reactive intermediate known as an ?,3-dehydrotoluene. This species is in the same oxidation state as a benzyne. Like benzynes, ?,3-dehydrotoluenes can be captured by various trapping agents to produce structurally diverse products that are complementary to those arising from the HDDA process. We call this new cycloisomerization process a pentadehydro-Diels-Alder (PDDA) reaction-a nomenclature chosen for chemical taxonomic reasons rather than mechanistic ones. In addition to alkynes, nitriles (RC?N), although non-participants in aza-HDDA reactions, readily function as the 2? component in PDDA cyclizations to produce, via trapping of the ?,3-(5-aza)dehydrotoluene intermediates, pyridine-containing products.

| S-EPMC4877333 | biostudies-literature

The hexadehydro-Diels-Alder reaction.

Project description:Arynes (aromatic systems containing, formally, a carbon-carbon triple bond) are among the most versatile of all reactive intermediates in organic chemistry. They can be 'trapped' to give products that are used as pharmaceuticals, agrochemicals, dyes, polymers and other fine chemicals. Here we explore a strategy that unites the de novo generation of benzynes-through a hexadehydro-Diels-Alder reaction-with their in situ elaboration into structurally complex benzenoid products. In the hexadehydro-Diels-Alder reaction, a 1,3-diyne is engaged in a [4+2] cycloisomerization with a 'diynophile' to produce the highly reactive benzyne intermediate. The reaction conditions for this simple, thermal transformation are notable for being free of metals and reagents. The subsequent and highly efficient trapping reactions increase the power of the overall process. Finally, we provide examples of how this de novo benzyne generation approach allows new modes of intrinsic reactivity to be revealed.

| S-EPMC3538845 | biostudies-literature

The Aza-hexadehydro-Diels-Alder Reaction.

Project description:The generation of pyridynes from diyne nitriles is reported. These cyano-containing precursors are analogues of the triyne substrates typically used for the hexadehydro-Diels-Alder (HDDA) cycloisomerization reactions that produce ring-fused benzynes. Hence, the new processes described represent aza-HDDA reactions. Depending on the location of the nitrile, either 3,4-pyridynes (from 1,3-diynes containing a tethered cyano group) or 2,3-pyridynes (from 1-cyanoethyne derivatives containing a tethered alkyne) are produced. In situ trapping of these reactive intermediates leads to highly substituted and functionalized pyridine derivatives. In several instances, unprecedented pyridyne trapping reactions are seen. Differences in reaction energetics between the aza-HDDA substrates and that of their analogous HDDA (triyne) substrates are discussed.

| S-EPMC6921493 | biostudies-literature

An on-surface Diels-Alder reaction.

Project description:The Diels-Alder reaction is one of the most popular reactions in organic chemistry. However, its use in the field of on-surface synthesis is hampered by the spatial restrictions of this cycloaddition reaction. Herein we selected a cyclic strained triyne to demonstrate an on-surface hexadehydro-Diels-Alder reaction in a single molecule. The reaction was studied in detail by means of atomic force microscopy (AFM) with CO-functionalized tips. Our results pave the way to use this iconic pericyclic reaction for on-surface synthesis, introducing the concept of atom economy in the field.

| S-EPMC9298865 | biostudies-literature

Continuous flow of nitroso Diels-Alder reaction.

Project description:Our flow reaction systems have provided quantitative yields of nitroso Diels-Alder products with no byproducts in cases of cyclic dienes without temperature and pressure controls. Additionally, the reaction times were significantly shortened by using homogeneous catalyst (CuCl) or heterogeneous reagent (MnO2) in comparison with batch reaction.

| S-EPMC4506248 | biostudies-other

Microwave-based reaction screening: tandem retro-Diels-Alder/Diels-Alder cycloadditions of o-quinol dimers.

Project description:We have accomplished a parallel screen of cycloaddition partners for o-quinols utilizing a plate-based microwave system. Microwave irradiation improves the efficiency of retro-Diels-Alder/Diels-Alder cascades of o-quinol dimers which generally proceed in a diastereoselective fashion. Computational studies indicate that asynchronous transition states are favored in Diels-Alder cycloadditions of o-quinols. Subsequent biological evaluation of a collection of cycloadducts has identified an inhibitor of activator protein-1 (AP-1), an oncogenic transcription factor.

| S-EPMC3214659 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

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