Browse
Submit Data
Databases
API
Help

Dataset Information

25 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

BET & ELF Quantum Topological Analysis of Neutral 2-Aza-Cope Rearrangement of γ-Alkenyl Nitrones.

ABSTRACT: The 2-Aza-Cope rearrangement of γ-alkenyl nitrones is a rare example of the neutral thermal 2-aza-Cope process that usually takes place with cationic species. During the rearrangement, a redistribution of bonds and electronic density occurs in one kinetic step. However, the introduction of substituents with different steric requirements and electronic features might alter the activation energies and the synchronicity of the reaction. The electron localization function (ELF) analysis and its application to Bonding Evolution Theory (BET) analysis within the context of Molecular Electron Density Theory (MEDT) is an excellent tool to monitor the electron density along the reaction coordinate and thus investigate in detail bond breaking and formation and the corresponding energy barriers. By analyzing topological ELF calculations of seventeen 2-aza-Cope nitrone rearrangements with selected substituents, the main factors influencing the synchronicity of the process were investigated. This MEDT study results revealed that the rearrangement is a non-polar process mostly influenced by steric factors rather than by electronic ones, and confirms the pseudoradical character of the process rather than any pericyclic electron-reorganization.

SUBMITTER: Merino P

PROVIDER: S-EPMC6151987 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

?-Amination of keto-nitrones via multihetero-Cope rearrangement employing an imidoyl chloride reagent.

Project description:?-Aminations of ketone-derived nitrones have been developed via [3,3]-rearrangement of the intermediates generated upon condensation with imidoyl chlorides. Careful reagent selection provides synthetically attractive amino protecting groups. The enediamide or ?'-carbamoyl enamide products can be hydrolyzed to the desired carbonyl, or exposed to electrophiles for further ?-functionalization.

| S-EPMC3545407 | biostudies-literature

Formation of Complex ?-Imino Esters via Multihetero-Cope Rearrangement of ?-Keto Ester Derived Nitrones.

Project description:A sequential benzoylation and multihetero-Cope rearrangement of ?-keto ester derived nitrones has been developed. The reaction furnishes a diverse array of complex ?-imino ester derivatives. The products can be transformed into amino alcohols via LiAlH4 reduction.

| S-EPMC6311990 | biostudies-literature

Synergistic catalysis for cascade allylation and 2-aza-cope rearrangement of azomethine ylides.

Project description:The efficient construction of enantiomerically enriched molecules from simple starting materials via catalytic asymmetric synthesis strategies is a key challenge in synthetic chemistry. Metallated azomethine ylides are commonly-used synthons for the preparation of N-heterocycles and α-amino acids. Remarkably, to date, the utilization of azomethine ylides for the facile access to chiral amines has proven elusive. Here, we report that a synergistic Cu/Ir-catalytic system combined with careful tuning of the steric congestion can be used to convert aldimine esters to a variety of chiral homoallylic amines via a cascade allylation/2-aza-Cope rearrangement. The elucidation of the distinct effects of each stereogenic center of the allylation intermediates on the stereochemical outcome and chirality transfer in the rearrangement further guided the selection of catalysts combination.

| S-EPMC6453969 | biostudies-literature

Asymmetric Synthesis of β-Amino Amides by Catalytic Enantioconvergent 2-Aza-Cope Rearrangement.

Project description:Dynamic kinetic resolutions of α-stereogenic-β-formyl amides in asymmetric 2-aza-Cope rearrangements are described. Chiral phosphoric acids catalyze this rare example of a non-hydrogenative DKR of a β-oxo acid derivative. The [3,3]-rearrangement occurs with high diastereo- and enantiocontrol, forming β-imino amides that can be deprotected to the primary β-amino amide or reduced to the corresponding diamine.

| S-EPMC4661081 | biostudies-literature

Total synthesis of sedum alkaloids via catalyst controlled aza-Cope rearrangement and hydroformylation with formaldehyde.

Project description:The catalytic asymmetric aminoallylation of chiral aldehydes is developed as a new method for the catalyst controlled synthesis of syn- and anti-1,3-aminoalcohols. This methodology is highlighted in the synthesis of the sedum alkaloids (+)-sedridine and (+)-allosedridine both of which have their final carbon incorporated during closure of the piperidine ring via a hydroformylation with formaldehyde.

| S-EPMC3582941 | biostudies-literature

Aza-cope rearrangement-mannich cyclizations for the formation of complex tricyclic amines: stereocontrolled total synthesis of (+/-)-gelsemine.

Project description:A detailed examination of the use of aza-Cope rearrangement-Mannich cyclization sequences for assembling the azatricyclo[4.4.0.0(2,8)]decane core of gelsemine is described. Iminium ions and N-acyloxyiminium ions derived from endo-oriented 1-methoxy- or 1-hydroxybicyclo[2.2.2]oct-5-enylamines do not undergo the first step of this sequence, cationic aza-Cope rearrangement, to form cis-hydroisoquinolinium ions. However, the analogous base-promoted oxy-aza-Cope rearrangement does take place to form cis-hydroisoquinolones containing functionality that allows iminium ions or N-acyloxyiminium ions to be generated regioselectively in a subsequent step. Mannich cyclization of cis-hydroisoquinolones prepared in this way efficiently assembles the azatricyclo[4.4.0.0(2,8)]decane unit of gelsemine. Using a sequential base-promoted oxy-aza-Cope rearrangement/Mannich cyclization sequence, gram quantities of azatricyclo[4.4.0.0(2,8)]decanone 18, a central intermediate in our total of (+/-)-gelsemine, were prepared from 3-methylanisole in 12 steps and 16% overall yield.

| S-EPMC2570375 | biostudies-literature

Expedient synthesis of fused azepine derivatives using a sequential rhodium(II)-catalyzed cyclopropanation/1-aza-Cope rearrangement of dienyltriazoles.

Project description:A general method for the formation of fused dihydroazepine derivatives from 1-sulfonyl-1,2,3-triazoles bearing a tethered diene is reported. The process involves an intramolecular cyclopropanation of an ?-imino rhodium(II) carbenoid, leading to a transient 1-imino-2-vinylcyclopropane intermediate which rapidly undergoes a 1-aza-Cope rearrangement to generate fused dihydroazepine derivatives in moderate to excellent yields. The reaction proceeds with similar efficiency on gram scale. The use of catalyst-free conditions leads to the formation of a novel [4.4.0] bicyclic heterocycle.

| S-EPMC4266427 | biostudies-literature

A cope rearrangement-based route to hexahydroazulenes.

Project description:2-exo-Vinyl-7-alkylidenenorbornanes, readily prepared from fulvene Diels-Alder adducts, undergo smooth Cope rearrangement at elevated temperatures to produce hexahydroazulene derivatives.

| S-EPMC3947830 | biostudies-literature

Catalytic asymmetric synthesis of quaternary trifluoromethyl α- to ε-amino acid derivatives <i>via</i> umpolung allylation/2-aza-Cope rearrangement.

Project description:In this study, we developed an efficient Ir-catalyzed cascade umpolung allylation/2-aza-Cope rearrangement of tertiary α-trifluoromethyl α-amino acid derivatives for the preparation of a variety of quaternary α-trifluoromethyl α-amino acids in high yields with excellent enantioselectivities. The umpolung reactivity empowered by the activation of the key isatin-ketoimine moiety obviates the intractable enantioselectivity control in Pd-catalyzed asymmetric linear α-allylation. In combination with quasi parallel kinetic resolution or kinetic resolution, the generality of this method is further demonstrated by the first preparation of enantioenriched quaternary trifluoromethyl β-, γ-, δ- and ε-amino acid derivatives.

| S-EPMC8162408 | biostudies-literature

N-heteroatom substitution effect in 3-aza-cope rearrangements.

Project description:BackgroundThe nature of the heteroatom substitution in the nitrogen of a 3-aza-Cope system is explored.ResultsWhile N-propargyl isoxazolin-5-ones suffer 3-aza-Cope rearrangements at 60°C, the corresponding N-propargyl pyrazol-5-ones need a higher temperature of 180°C for the equivalent reaction. When the propargyl group is substituted by an allyl group, the temperature of the rearrangement for both type of compounds is less affected by the nature of the heteroatom present. Treatment with a base, such as ethoxide, facilitates the rearrangement, and in the case of isoxazol-5- ones other ring opening reactions take precedence, involving N-O ring cleavage of the 5-membered ring. However when base-catalysed decomposition is prevented by substituents, products arising from a room temperature aza-Cope rearrangement are isolated. A possible mechanistic pathway based on free energies derived from density functional calculations involving cyclic intermediates is proposed.ConclusionsThe nature of the heteroatom substitution in the nitrogen of a 3-aza-Cope system leads to a remarkable difference in the energy of activation of the reaction.

| S-EPMC3702470 | 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