Browse
Submit Data
Databases
API
Help

Dataset Information

30 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

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

ABSTRACT: 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.

SUBMITTER: Wei L

PROVIDER: S-EPMC6453969 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Enantioselective Catalysis of an Anionic Oxy-Cope Rearrangement Enabled by Synergistic Ion Binding.

Project description:Charge-accelerated rearrangements present interesting challenges to enantioselective catalysis, due in large part to the competing requirements for maximizing reactivity (ion-pair separation) and stereochemical communication. Herein, we describe application of a synergistic ion-binding strategy to catalyze the anionic oxy-Cope rearrangement of a symmetric bis-styrenyl allyl alcohol in up to 75:25 e.r. Structure-reactivity-selectivity relationship studies, including linear free-energy-relationship analyses, with bifunctional urea catalysts indicate that H-bonding and cation-binding interactions act cooperatively to promote the chemo- and enantioselective [3,3]-rearrangement. Implications for catalyst designs applicable to other transformations involving oxyanionic intermediates are discussed.

| S-EPMC7592710 | 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

Direct C(sp<sup>3</sup>)-H allylation of 2-alkylpyridines with Morita-Baylis-Hillman carbonates via a tandem nucleophilic substitution/aza-Cope rearrangement.

Project description:A base- and catalyst-free C(sp3)-H allylic alkylation of 2-alkylpyridines with Morita-Baylis-Hillman (MBH) carbonates is described. A plausible mechanism of the reaction might involve a tandem SN2' type nucleophilic substitution followed by an aza-Cope rearrangement. Various alkyl substituents on 2-alkylpyridines were tolerated in the reaction to give the allylation products in 26-91% yields. The developed method provides a straightforward and operational simple strategy for the allylic functionalization of 2-alkypyridine derivatives.

| S-EPMC8491709 | 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

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

Project description: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.

| S-EPMC6151987 | biostudies-literature

Hapalindole/Ambiguine Biogenesis Is Mediated by a Cope Rearrangement, C-C Bond-Forming Cascade.

Project description:Hapalindoles are bioactive indole alkaloids with fascinating polycyclic ring systems whose biosynthetic assembly mechanism has remained unknown since their initial discovery in the 1980s. In this study, we describe the fam gene cluster from the cyanobacterium Fischerella ambigua UTEX 1903 encoding hapalindole and ambiguine biosynthesis along with the characterization of two aromatic prenyltransferases, FamD1 and FamD2, and a previously undescribed cyclase, FamC1. These studies demonstrate that FamD2 and FamC1 act in concert to form the tetracyclic core ring system of the hapalindoles from cis-indole isonitrile and geranyl pyrophosphate through a presumed biosynthetic Cope rearrangement and subsequent 6-exo-trig cyclization/electrophilic aromatic substitution reaction.

| S-EPMC4681624 | biostudies-literature

Stereodivergent Allylation of Azaaryl Acetamides and Acetates by Synergistic Iridium and Copper Catalysis.

Project description:We report stereodivergent allylic substitution reactions of allylic esters with prochiral enolates derived from azaaryl acetamides and acetates to form products from addition of the enolates at the most substituted carbon of an allyl moiety with two catalysts, a chiral metallacyclic iridium complex and a chiral bisphosphine-ligated copper(I) complex, which individually control the configuration of the electrophilic and nucleophilic carbon atoms, respectively. By simple permutations of enantiomers of the two catalysts, all four stereoisomers of products containing two stereogenic centers were synthesized individually with high diastereoselectivity and enantioselectivity. A variety of azaaryl acetamides and acetates bearing pyridyl, benzothiazolyl, benzoxazolyl, pyrazinyl, quinolinyl and isoquinolinyl moieties were all found to be suitable for this transformation.

| S-EPMC5812688 | biostudies-literature

[3 + 2] Cycloaddition with photogenerated azomethine ylides in β-cyclodextrin.

Project description:Stability constants for the inclusion complexes of cyclohexylphthalimide 2 and adamantylphthalimide 3 with β-cyclodextrin (β-CD) were determined by 1H NMR titration, K = 190 ± 50 M-1, and K = 2600 ± 600 M-1, respectively. Photochemical reactivity of the inclusion complexes 2@β-CD and 3@β-CD was investigated, and we found out that β-CD does not affect the decarboxylation efficiency, while it affects the subsequent photochemical H-abstraction, resulting in different product distribution upon irradiation in the presence of β-CD. The formation of ternary complexes with acrylonitrile (AN) and 2@β-CD or 3@β-CD was also essayed by 1H NMR. Although the formation of such complexes was suggested, stability constants could not be determined. Irradiation of 2@β-CD in the presence of AN in aqueous solution where cycloadduct 7 was formed highly suggests that decarboxylation and [3 + 2] cycloaddition take place in the ternary complex, whereas such a reactivity from bulky adamantane 3 is less likely. This proof of principle that decarboxylation and cycloaddition can be performed in the β-CD cavity has a significant importance for the design of new supramolecular systems for the control of photoreactivity.

| S-EPMC7296198 | 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

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