Browse
Submit Data
Databases
API
Help

Dataset Information

23 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Acetoxy Meldrum's acid: a versatile acyl anion equivalent in the Pd-catalyzed asymmetric allylic alkylation.

ABSTRACT: Acetoxy Meldrum's acid can serve as a versatile acyl anion equivalent in the Pd-catalyzed asymmetric allylic alkylation. The reaction of this nucleophile with various meso and racemic electrophiles afforded alkylated products in high yields and enantiopurities. These enantioenriched products are versatile intermediates that can be further functionalized using nitrogen- and oxygen-centered nucleophiles, affording versatile scaffolds for the synthesis of nucleoside analogues. These scaffolds were used to complete formal syntheses of the anti-HIV drugs carbovir, abacavir, and the antibiotic aristeromycin.

SUBMITTER: Trost BM

PROVIDER: S-EPMC3144701 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Acetoxy Meldrum's acid: a versatile acyl anion equivalent in the Pd-catalyzed asymmetric allylic alkylation.

Trost Barry M BM Osipov Maksim M Kaib Philip S J PS Sorum Mark T MT

Organic letters 20110526 12

Acetoxy Meldrum's acid can serve as a versatile acyl anion equivalent in the Pd-catalyzed asymmetric allylic alkylation. The reaction of this nucleophile with various meso and racemic electrophiles afforded alkylated products in high yields and enantiopurities. These enantioenriched products are versatile intermediates that can be further functionalized using nitrogen- and oxygen-centered nucleophiles, affording versatile scaffolds for the synthesis of nucleoside analogues. These scaffolds were ...[more]

PMID: 21615099

Similar Datasets

Regio- and stereospecific rhodium-catalyzed allylic alkylation with an acyl anion equivalent: an approach to acyclic α-ternary β,γ-unsaturated aryl ketones.

Project description:The regio- and stereospecific rhodium-catalyzed allylic alkylation of secondary allylic carbonates with cyanohydrin pronucleophiles facilitates the direct construction of acyclic α-ternary β,γ-unsaturated aryl ketones. Interestingly, this study illustrates the impact of deaggregating agents on regiocontrol and the electronic nature of the aryl component to suppress olefin isomerization. In addition, we demonstrate that the dimethylamino substituent, which modulates the pKa of the α-ternary β,γ-unsaturated aryl ketone, provides a useful synthetic handle for further functionalization via Kumada cross-coupling of the aryl trimethylammonium salt. Finally, the stereospecific alkylation of a chiral nonracemic secondary allylic carbonate affords the enantioenriched α-ternary aryl ketone, which was employed in a formal synthesis of trichostatic acid to illustrate that the allylic alkylation proceeds with net retention of configuration.

| S-EPMC5433512 | biostudies-literature

Total synthesis of enantiopure (+)-gamma-lycorane using highly efficient Pd-catalyzed asymmetric allylic alkylation.

Project description:[reaction: see text] A highly efficient short total synthesis of (+)-gamma-lycorane (>99% ee, 41% overall yield) was achieved by using the asymmetric allylic alkylation in the key step catalyzed by palladium complexes with novel chiral biphenol-based monodentate phosphoramidite ligands.

| S-EPMC2562274 | biostudies-other

Construction of Tertiary Chiral Centers by Pd-catalyzed Asymmetric Allylic Alkylation of Prochiral Enolate Equivalents.

Project description:The palladium-catalyzed decarboxylative allylic alkylation of enol carbonates derived from lactams and ketones is described. Employing these substrates with an electronically tuned Pd catalyst system trisubstituted chiral centers are produced. These stereocenters have been previously challenging to achieve using Pd complex/chiral P-N ligand systems.

| S-EPMC4528676 | biostudies-literature

Palladium-catalyzed asymmetric allylic alpha-alkylation of acyclic ketones.

Project description:The first example of Pd-catalyzed asymmetric allyl alkylation of the conformationally nonrigid acyclic ketone enolates is reported with excellent yields, regioselectivity, and enantioselectivity. The double bond geometry of the allyl enol carbonates affects its reactivity, selectivity, as well as the absolute configuration of the products. An opposite enantioselectivity from what is predicted by a direct attack of the enolate on the allyl moiety of the pi-ally-Pd complex was observed. An alternative mechanism was proposed, which involves an inner sphere process of coordination of the enolate to Pd followed by reductive elimination.

| S-EPMC2533158 | biostudies-literature

Palladium-catalyzed decarboxylative asymmetric allylic alkylation of enol carbonates.

Project description:Palladium-catalyzed decarboxylative asymmetric allylic alkylation (DAAA) of allyl enol carbonates as a highly chemo-, regio-, and enantioselective process for the synthesis of ketones bearing either a quaternary or a tertiary alpha-stereogenic center has been investigated in detail. Chiral ligand L4 was found to be optimal in the DAAA of a broad scope of cyclic and acyclic ketones including simple aliphatic ketones with more than one enolizable proton. The allyl moiety of the carbonates has been extended to a variety of cyclic or acyclic disubstituted allyl groups. Our mechanistic studies reveal that, similar to the direct allylation of lithium enolates, the DAAA reaction proceeds through an "outer sphere" S(N)2 type of attack on the pi-allylpalladium complex by the enolate. An important difference between the DAAA reaction and the direct allylation of lithium enolates is that in the DAAA reaction, the nucleophile and the electrophile were generated simultaneously. Since the pi-allylpalladium cation must serve as the counterion for the enolate, the enolate probably exists as a tight-ion-pair. This largely prevents the common side reactions of enolates associated with the equilibrium between different enolates. The much milder reaction conditions as well as the much broader substrate scope also represent the advantages of the DAAA reaction over the direct allylation of preformed metal enolates.

| S-EPMC2804400 | biostudies-literature

Palladium-Catalyzed Decarboxylative Asymmetric Allylic Alkylation of Thietane 1,1-Dioxides.

Project description:A palladium-catalyzed decarboxylative asymmetric allylic alkylation of thietane 1,1-dioxides via linear enolate intermediates from racemic starting materials has been developed. This process installs an α-sulfonyl tetrasubstituted stereogenic center with high enantioselectivity. The potential to transform the alkylated products to novel types of enantioenriched spirocycles for medicinal chemistry applications has also been demonstrated.

| S-EPMC8762707 | biostudies-literature

Palladium-Catalyzed Decarboxylative Asymmetric Allylic Alkylation of 1,4-Diazepan-5-ones.

Project description:We report the palladium-catalyzed asymmetric allylic alkylation of 1,4-diazepan-5-ones. This reaction proceeds smoothly to give gem-disubstituted diazepanone heterocycles bearing various functional groups in up to >99% yield and up to 95% ee. An electron-rich p-anisoyl lactam protecting group and the use of a nonpolar solvent proved crucial to obtaining high enantioselectivity in most cases. Additionally, we demonstrate the use of our methodology in the synthesis of a gem-disubstituted analogue of the FDA-approved anti-insomnia drug suvorexant.

| S-EPMC8579948 | biostudies-literature

Palladium-catalyzed asymmetric allylic alkylation (AAA) with alkyl sulfones as nucleophiles.

Project description:An efficient palladium-catalyzed AAA reaction with a simple α-sulfonyl carbon anion as nucleophiles is presented for the first time. Allyl fluorides are used as superior precursors for the generation of π-allyl complexes that upon ionization liberate fluoride anions for activation of silylated nucleophiles. With the unique bidentate diamidophosphite ligand ligated palladium as catalyst, the in situ generated α-sulfonyl carbon anion was quickly captured by the allylic intermediates, affording a series of chiral homo-allylic sulfones with high efficiency and selectivity. This work provides a mild in situ desilylation strategy to reveal nucleophilic carbon centers that could be used to overcome the pK a limitation of "hard" nucleophiles in enantioselective transformations.

| S-EPMC8356815 | biostudies-literature

Effective synthesis of bicyclodienes via palladium-catalyzed asymmetric allylic alkylation and ruthenium-catalyzed cycloisomerization.

Project description:[n.3.0]Bicycles (n = 3-6) can be synthesized using palladium-catalyzed asymmetric allylic alkylation followed by ruthenium-catalyzed cycloisomerization. New types of triarylphosphino-1,2-diaminooxazoline ligands show the same high levels of enantioselectivity observed with Trost ligand when employed in Pd-catalyzed allylic alkylation reactions. The enyne products of these allylic alkylation reactions were further elaborated using a Ru-catalyzed redox isomerization process, for which a mechanism is proposed.

| S-EPMC7772093 | biostudies-literature

Enantio-, diastereo-, and regioselective iridium-catalyzed asymmetric allylic alkylation of acyclic ?-ketoesters.

Project description:The first regio-, diastereo-, and enantioselective allylic alkylation of acyclic ?-ketoesters to form vicinal tertiary and all-carbon quaternary stereocenters is reported. Critical to the successful development of this method was the employment of iridium catalysis in concert with N-aryl-phosphoramidite ligands. Broad functional group tolerance is observed at the keto-, ester-, and ?-positions of the nucleophile. Various transformations demonstrating the utility of this method for rapidly accessing complex enantioenriched compounds are reported.

| S-EPMC3881553 | 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