Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Facile Synthesis of 3-Amido-Dienynes via a Tandem ?-Propargylation-Isomerization of Chiral Allenamides and their Applications in Diels-Alder Cycloadditions.

ABSTRACT: A series of de novo 3-amido-dienynes was synthesized via tandem ?-propargylation-isomerization of chiral allenamides with moderate E/Z ratio. Reactivities of E-and Z-isomers were examined.

SUBMITTER: Ma ZX

PROVIDER: S-EPMC6000824 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Facile Synthesis of 3-Amido-Dienynes via a Tandem α-Propargylation-Isomerization of Chiral Allenamides and their Applications in Diels-Alder Cycloadditions.

Ma Zhi-Xiong ZX Fang Li-Chao LC Hsung Richard P RP

Synlett : accounts and rapid communications in synthetic organic chemistry 20170901 20

A series of de novo 3-amido-dienynes was synthesized via tandem α-propargylation-isomerization of chiral allenamides with moderate E/Z ratio. Reactivities of E-and Z-isomers were examined. ...[more]

PMID: 29910538

Similar Datasets

Torquoselective ring closures of chiral amido trienes derived from allenamides. A tandem allene isomerization-pericyclic ring-closure-intramolecular Diels-Alder cycloaddition.

Project description:A new torquoselective ring-closure of chiral amide-substituted 1,3,5-hexatrienes and its application in tandem with [4 + 2] cycloaddition are described. The trienes were derived via either a 1,3-H or 1,3-H-1,7-H shift of alpha-substituted allenamides, and the entire sequence through the [4 + 2] cycloaddition could be in tandem from allenamides.

| S-EPMC2862010 | biostudies-literature

Oppolzer-type intramolecular Diels-Alder cycloadditions via isomerizations of allenamides.

Project description:A new approach to Oppolzer's intramolecular Diels-Alder cycloaddition (IMDA) through γ-isomerization of readily available N-tethered allenamides is described. These IMDA reactions are carried out in tandem with the allenamide isomerization or 1,3-H shift, leading to complex nitrogen heterocycles in a highly stereoselective manner.

| S-EPMC3112474 | biostudies-literature

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

Origins of stereoselectivity in Diels-Alder cycloadditions catalyzed by chiral imidazolidinones.

Project description:B3LYP/6-31G(d) density functional theory has been used to study Diels-Alder reactions of cyclopentadiene with alpha,beta-unsaturated aldehydes and ketones organocatalyzed by MacMillan's chiral imidazolidinones. Preferred conformations of transition structures and reaction intermediates have been located. The dramatically different reactivities and enantioselectivities exhibited by two similar chiral imidazolidinones are rationalized.

| S-EPMC3164120 | biostudies-literature

Thermal intramolecular [4 + 2] cycloadditions of allenamides: a stereoselective tandem propargyl amide isomerization-cycloaddition.

Project description:A stereoselective intramolecular normal demand [4 + 2] cycloaddition of allenamides under thermal conditions without metal assistance is described. This work led to the development of a stereoselective tandem propargyl amide-isomerization-[4 + 2] cycloaddition sequence amenable for rapid assembly of complex nitrogen heterocycles.

| S-EPMC2736324 | biostudies-literature

A highly stereoselective Diels-Alder cycloaddition of enones with chiral cyclic 2-amidodienes derived from allenamides.

Project description:Lewis acid promoted Diels-Alder cycloadditions of a series of de novo chiral cyclic 2-amidodienes are described. These cyclic 2-amidodienes are derived from chiral α-allyl allenamides via a sequence of E-selective 1,3-H shift and 6π-electron pericyclic ring closure. With enones serving as effective dienophiles, these cycloadditions can be highly diastereoselective depending upon the chiral amide substituent, thereby representing a facile entry to optically enriched [2.2.2]bicyclic manifolds.

| S-EPMC3823681 | biostudies-literature

Regio- and stereoselective isomerizations of allenamides: synthesis of 2-amido-dienes and their tandem isomerization-electrocyclic ring-closure.

Project description:A regio- and stereoselective isomerization of allenamides is described, leading to preparations of de novo 2-amido-dienes and a tandem isomerization-6pi-electron electrocyclic ring-closure.

| S-EPMC2732350 | biostudies-literature

Diels-Alder cycloadditions of strained azacyclic allenes.

Project description:For over a century, the structures and reactivities of strained organic compounds have captivated the chemical community. Whereas triple-bond-containing strained intermediates have been well studied, cyclic allenes have received far less attention. Additionally, studies of cyclic allenes that bear heteroatoms in the ring are scarce. We report an experimental and computational study of azacyclic allenes, which features syntheses of stable allene precursors, the mild generation and Diels-Alder trapping of the desired cyclic allenes, and explanations of the observed regio- and diastereoselectivities. Furthermore, we show that stereochemical information can be transferred from an enantioenriched silyl triflate starting material to a Diels-Alder cycloadduct by way of a stereochemically defined azacyclic allene intermediate. These studies demonstrate that heteroatom-containing cyclic allenes, despite previously being overlooked as valuable synthetic intermediates, may be harnessed for the construction of complex molecular scaffolds bearing multiple stereogenic centres.

| S-EPMC6317513 | biostudies-literature

Versatile Peptide Macrocyclization with Diels-Alder Cycloadditions.

Project description:Macrocyclization can improve bioactive peptide ligands through preorganization of molecular topology, leading to improvement of pharmacologic properties like binding affinity, cell permeability, and metabolic stability. Here we demonstrate that Diels-Alder [4 + 2] cycloadditions can be harnessed for peptide macrocyclization and stabilization within a range of peptide scaffolds and chemical environments. Diels-Alder cyclization of diverse diene-dienophile reactive pairs proceeds rapidly, in high yield and with tunable stereochemical preferences on solid-phase or in aqueous solution. This reaction can be applied alone or in concert with other stabilization chemistries, such as ring-closing olefin metathesis, to stabilize loop, turn, and ?-helical secondary structural motifs. NMR and molecular dynamics studies of model loop peptides confirmed preferential formation of endo cycloadduct stereochemistry, imparting significant structural rigidity to the peptide backbone that resulted in augmented protease resistance and increased biological activity of a Diels-Alder cyclized (DAC) RGD peptide. Separately, we demonstrated the stabilization of DAC ?-helical peptides derived from the ER?-binding protein SRC2. We solved a 2.25 Å cocrystal structure of one DAC helical peptide bound to ER?, which unequivocally corroborated endo stereochemistry of the resulting Diels-Alder adduct, and confirmed that the unique architecture of stabilizing motifs formed with this chemistry can directly contribute to target binding. These data establish Diels-Alder cyclization as a versatile approach to stabilize diverse protein structural motifs under a range of chemical environments.

| S-EPMC7745206 | biostudies-literature

Radical cation Diels-Alder cycloadditions by visible light photocatalysis.

Project description:Ruthenium(II) polypyridyl complexes promote the efficient radical cation Diels-Alder cycloaddition of electron-rich dienophiles upon irradiation with visible light. These reactions enable facile [4 + 2] cycloadditions that would be electronically mismatched under thermal conditions. Key to the success of this methodology is the availability of ligand-modified ruthenium complexes that enable rational tuning of the electrochemical properties of the catalyst without significantly perturbing the overall photophysical properties of the system.

| S-EPMC3227774 | 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