Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

A stereoselective synthesis of digitoxin and digitoxigen mono- and bisdigitoxoside from digitoxigenin via a palladium-catalyzed glycosylation.

ABSTRACT: A convergent and stereocontrolled route to trisaccharide natural product digitoxin has been developed. The route is amenable to the preparation of both the digitoxigen mono- and bisdigitoxoside. This route featured the iterative application of the palladium-catalyzed glycosylation reaction, reductive 1,3-transposition, diastereoselective dihydroxylation, and regioselective protection. The natural product digitoxin was fashioned in 15 steps starting from digitoxigenin 2 and pyranone 8a or 18 steps from achiral acylfuran.

SUBMITTER: Zhou M

PROVIDER: S-EPMC2527289 | biostudies-literature | 2006 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

A stereoselective synthesis of digitoxin and digitoxigen mono- and bisdigitoxoside from digitoxigenin via a palladium-catalyzed glycosylation.

Zhou Maoquan M O'Doherty George A GA

Organic letters 20060901 19

A convergent and stereocontrolled route to trisaccharide natural product digitoxin has been developed. The route is amenable to the preparation of both the digitoxigen mono- and bisdigitoxoside. This route featured the iterative application of the palladium-catalyzed glycosylation reaction, reductive 1,3-transposition, diastereoselective dihydroxylation, and regioselective protection. The natural product digitoxin was fashioned in 15 steps starting from digitoxigenin 2 and pyranone 8a or 18 step ...[more]

PMID: 16956221

Similar Datasets

Palladium-Catalyzed ?-Stereoselective O-Glycosylation of O(3)-Acylated Glycals.

Project description:Pd(MeCN)2Cl2 enables the ?-stereoselective catalytic synthesis of 2,3-unsaturated O-glycosides from O(3)-acylated glycals without the requirement for additives to preactivate either donor or nucleophile. Mechanistic studies suggest that, unlike traditional (?3-allyl)palladium-mediated processes, the reaction proceeds via an alkoxy-palladium intermediate that increases the proton acidity and oxygen nucleophilicity of the alcohol. The method is exemplified with the synthesis of a range of glycosides and glycoconjugates of synthetic utility.

| S-EPMC5479629 | biostudies-literature

De novo asymmetric synthesis of homoadenosine via a palladium-catalyzed N-glycosylation.

Project description:[reaction: see text] A highly stereoselective synthesis of l-2-deoxy-beta-ribo-hexopyranosyl nucleosides from 6-chloropurine and Boc-protected pyranone has been developed. Our approach relies on the iterative application of a palladium-catalyzed N-glycosylation, diastereoselective reduction, and reductive 1,3-transposition. This strategy is amenable to prepare various natural and unnatural hexopyranosyl nucleosides analogues.

| S-EPMC2546502 | biostudies-literature

Palladium-Catalyzed Direct Stereoselective Synthesis of Deoxyglycosides from Glycals.

Project description:Palladium(II) in combination with a monodentate phosphine ligand enables the unprecedented direct and α-stereoselective catalytic synthesis of deoxyglycosides from glycals. Initial mechanistic studies suggest that in the presence of N-phenyl-2-(di-tert-butylphosphino)pyrrole as the ligand, the reaction proceeds via an alkoxy palladium intermediate that increases the proton acidity and oxygen nucleophilicity of the alcohol. The method is demonstrated with a wide range of glycal donors and acceptors, including substrates bearing alkene functionalities.

| S-EPMC5484376 | biostudies-literature

Stereoselective Cyclopropanation of 1,1-Diborylalkenes via Palladium-Catalyzed (Trimethylsilyl)diazomethane Insertion.

Project description:Palladium catalyzes the cyclopropanation of 2-substituted 1,1-diborylalkenes with (trimethylsilyl)diazomethane. The relative stereoselectivity is controlled via a carbene insertion sequence generating an exclusive anti conformation between the R and SiMe3 substituents. Mixed 1,1-diborylalkenes also contributed to the formation of stereoselective B, B, Si-cyclopropanes. Orthogonal activation with NaOtBu gives protodeborylation preferentially on the boron moiety syn to the aryl group. Further oxidation gives access to polyfunctional cyclopropyl alcohols with controlled enantioselectivity when chiral boryl motifs are involved.

| S-EPMC9348837 | biostudies-literature

Stereoselective synthesis of cyclic ethers via the palladium-catalyzed intramolecular addition of alcohols to phosphono allylic carbonates.

Project description:Cross metathesis of the acrolein-derived phosphono allylic carbonate and hydroxy alkenes using second generation Grubbs catalyst and copper(I) iodide gave the substituted phosphonates in good yield. Stereospecific palladium(0)-catalyzed cyclization gave tetrahydrofuran and tetrahydropyran vinyl phosphonates. Regioselective Wacker oxidation of the vinyl phosphonate gave the beta-keto phosphonate, which underwent HWE reaction with benzaldehyde to yield the unsaturated ketone. The utility of the cross metathesis/cyclization protocol was further demonstrated by a formal synthesis of centrolobine.

| S-EPMC2717013 | biostudies-literature

Stereoselective isoxazolidine synthesis via copper-catalyzed alkene aminooxygenation.

Project description:Isoxazolidines are useful in organic synthesis, drug discovery, and chemical biology endeavors. A new stereoselective synthesis of methyleneoxy-substituted isoxazolidines is disclosed. The method involves copper-catalyzed aminooxygenation/cyclization of N-sulfonyl-O-butenyl hydroxylamines in the presence of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl radical (TEMPO) and O(2) and provides substituted isoxazolidines in excellent yields and diastereoselectivities. We also demonstrate selective mono N-O reduction followed by oxidation of the remaining N-O bond to reveal a 2-amino-γ-lactone. Reduction of the γ-lactone reveals the corresponding aminodiol.

| S-EPMC3465949 | biostudies-literature

Stereoselective Synthesis of Isoxazolidines via Copper-Catalyzed Alkene Diamination.

Project description:A convenient copper-catalyzed intramolecular/intermolecular alkene diamination reaction to synthesize 3-aminomethyl-functionalized isoxazolidines under mild reaction conditions and with generally high levels of diastereoselectivity was achieved. This reaction demonstrates that previously underutilized unsaturated carbamates are good [Cu]-catalyzed diamination substrates. Sulfonamides, anilines, benzamide, morpholine, and piperidine can serve as the external amine source. This relatively broad amine range is attributed to the mild reaction conditions. Reduction of the N-O bond could also be achieved, revealing the corresponding 3,4-diamino-1-alcohols efficiently.

| S-EPMC5944859 | biostudies-literature

Synthesis of 3-Substituted Pyrrolidines via Palladium-Catalyzed Hydroarylation.

Project description:Metal-catalyzed reactions have revolutionized synthetic chemistry, allowing access to unprecedented molecular architectures with powerful properties and activities. Nonetheless, some transformations remain sparse in number, or out of reach, even with the diverse modern catalytic chemical arsenal, including bimolecular alkene hydroarylation reactions. We report here a broad-scope, palladium-catalyzed pyrroline hydroarylation process that gives 3-aryl pyrrolidines, a class of small molecules with potency in a diverse range of biological scenarios. Thus, whereas N-acyl pyrrolines usually undergo palladium-catalyzed arylation to give alkene products, the corresponding reactions of N-alkyl pyrrolines deliver products of hydroarylation, pyrrolidines. The process has broad substrate scope and can be used to directly deliver drug-like molecules in a single step from readily available precursors.

| S-EPMC6240703 | biostudies-literature

Stereoselective synthesis of tricyclic compounds by intramolecular palladium-catalyzed addition of aryl iodides to carbonyl groups.

Project description:Starting from ?-ketoesters with an o-iodobenzyl group we studied a palladium-catalyzed cyclization process that stereoselectively led to bi- and tricyclic compounds in moderate to excellent yields. Four X-ray crystal structure analyses unequivocally defined the structure of crucial cyclization products. The relative configuration of the precursor compounds is essentially transferred to that of the products and the formed hydroxy group in the newly generated cyclohexane ring is consistently in trans-arrangement with respect to the methoxycarbonyl group. A transition-state model is proposed to explain the observed stereochemical outcome. This palladium-catalyzed Barbier-type reaction requires a reduction of palladium(II) back to palladium(0) which is apparently achieved by the present triethylamine.

| S-EPMC4979759 | biostudies-other

Palladium-Catalyzed Stereoselective Construction of 1,3-Stereocenters Displaying Axial and Central Chirality via Asymmetric Alkylations.

Project description:The concurrent construction of 1,3-stereocenters remains a challenge. Herein, we report the development of stereoselective union of a point chiral center with allenyl axial chirality in 1,3-position by Pd-catalyzed asymmetric allenylic alkylation between racemic allenyl carbonates and indanone-derived β-ketoesters. Various target products bearing a broad range of functional groups were afforded in high yield (up to 99%) with excellent enantioselectivities (up to 98% ee) and good diastereoselectivities (up to 13:1 dr).

| S-EPMC10096308 | 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