Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Lewis Acid Mediated Vinylogous Additions of Enol Nucleophiles into an ?,?-Unsaturated Platinum Carbene.

ABSTRACT: A variety of substituted indoles and benzofurans are accessed via a platinum catalyzed annulation and vinylogous addition of enol nucleophiles. Several ?-dicarbonyl compounds participate in the reaction, as do ?-nitro and ?-cyano carbonyl species. Subjecting the indole products to acidic conditions results in the formation of fused heterocycles.

SUBMITTER: Allegretti PA

PROVIDER: S-EPMC4732870 | biostudies-literature | 2016 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Lewis Acid Mediated Vinylogous Additions of Enol Nucleophiles into an α,β-Unsaturated Platinum Carbene.

Allegretti Paul A PA Huynh Khoi K Ozumerzifon Tarik J TJ Ferreira Eric M EM

Organic letters 20151214 1

A variety of substituted indoles and benzofurans are accessed via a platinum catalyzed annulation and vinylogous addition of enol nucleophiles. Several β-dicarbonyl compounds participate in the reaction, as do α-nitro and α-cyano carbonyl species. Subjecting the indole products to acidic conditions results in the formation of fused heterocycles. ...[more]

PMID: 26652926

Similar Datasets

Synthesis of tetrahydropyridazines by a metal-carbene-directed enantioselective vinylogous N-H insertion/Lewis acid-catalyzed diastereoselective Mannich addition.

Project description:A versatile cascade of reactions, triggered by Rh(II)-catalyzed diazo decomposition followed by a vinylogous N-H insertion/Lewis acid catalyzed Mannich addition, that produces highly substituted 1,2,3,6-tetrahydropyridazines in up to 97 % ee with high yield and diastereocontrol has been developed.

| S-EPMC3517037 | biostudies-literature

The vinylogous aldol reaction of unsaturated esters and enolizable aldehydes using the novel Lewis acid aluminum tris(2,6-di-2-naphthylphenoxide).

Project description:The synthesis of the novel Lewis acid, aluminum tris(2,6-di-2-naphthylphenoxide) (ATNP), and its use in the vinylogous aldol reaction between methyl crotonate and enolizable aldehydes are described. ATNP is related to Yamamoto's Lewis acid, aluminum tris(2,6-diphenylphenoxide) (ATPH), but the 2-naphthyl groups more effectively block the ?-position of aldehydes, enabling the selective enolization of crotonate esters in the presence of enolizable aldehydes. Vinylogous aldol reactions then proceed smoothly and in high yields with a variety of substrates.

| S-EPMC3427784 | biostudies-literature

Synthesis of amino acid derived enaminones via Wolff rearrangement using vinylogous amides as carbon nucleophiles.

Project description:Cyclic enaminones were synthesized in high yields from amino acids in two steps via Wolff rearrangement. The cyclization represents a rare 6-exo-dig cyclization involving a ketene as an electrophile. No racemization was observed during this reaction.

| S-EPMC2974010 | biostudies-literature

Rhodium-catalyzed enantioselective vinylogous addition of enol ethers to vinyldiazoacetates.

Project description:A highly asymmetric vinylogous addition of acyclic silyl enol ethers to siloxyvinyldiazoacetate is described. The reaction features a diastereoselective 1,4-siloxy group migration event. Products are obtained in up to 97% ee. When more sterically crowded silyl enol ethers are employed, an enantioselective formal [3+2] cycloaddition becomes the dominant reaction pathway. Control experiments reveal the (Z)-olefin geometry to be critical for high levels of enantiocontrol.

| S-EPMC3549400 | biostudies-literature

Platinum-Catalyzed α,β-Unsaturated Carbene Formation in the Formal Syntheses of Frondosin B and Liphagal.

Project description:Formal syntheses of tetracyclic terpenoids frondosin B and liphagal are described. Both synthetic routes rely on the use of platinum-catalyzed α,β-unsaturated carbene formation for the key C-C bond forming transformations. The successful route toward frondosin B utilizes a formal (4 + 3) cycloaddition, while the liphagal synthesis features the vinylogous addition of an enol nucleophile as a key step. Both synthetic routes are discussed, revealing insights into structural requirements in the catalytic α,β-unsaturated carbene reaction manifold.

| S-EPMC5369019 | biostudies-literature

Enantioselective conjugate additions of ?-amino radicals via cooperative photoredox and Lewis acid catalysis.

Project description:We report the highly enantioselective addition of photogenerated ?-amino radicals to Michael acceptors. This method features a dual-catalyst protocol that combines transition metal photoredox catalysis with chiral Lewis acid catalysis. The combination of these two powerful modes of catalysis provides an effective, general strategy to generate and control the reactivity of photogenerated reactive intermediates.

| S-EPMC4547529 | biostudies-literature

Lewis acid-catalyzed asymmetric reactions of β,γ-unsaturated 2-acyl imidazoles.

Project description:The investigation of diverse reactivity of β,γ-unsaturated carbonyl compounds is of great value in asymmetric catalytic synthesis. Numerous enantioselective transformations have been well developed with β,γ-unsaturated carbonyl compounds as nucleophiles, however, few example were realized by utilizing them as not only nucleophiles but also electrophiles under a same catalytic system. Here we report a regioselective catalytic asymmetric tandem isomerization/α-Michael addition of β,γ-unsaturated 2-acyl imidazoles in the presence of chiral N,N'-dioxide metal complexes, delivering a broad range of optically pure 1,5-dicarbonyl compounds with two vicinal tertiary carbon stereocenters in up to >99% ee under mild conditions. Meanwhile, stereodivergent synthesis is disclosed to yield all four stereoisomers of products. Control experiments suggest an isomerization process involved in the reaction and give an insight into the role of NEt3. In addition, Mannich reaction and sulfur-Michael addition of β,γ-unsaturated 2-acyl imidazoles proceed smoothly as well under the same catalytic system.

| S-EPMC7398931 | biostudies-literature

N-heterocyclic carbene-catalyzed conjugate additions of alcohols.

Project description:An efficient intermolecular conjugate addition of alcohols to activated alkenes catalyzed by N-heterocyclic carbenes has been developed. With 5 mol % of the free carbene derived from IMes·HCl, unsaturated ketones and esters are competent substrates, and a variety of primary and secondary alcohols can be employed as the nucleophile. No oligomerization is observed under these mild conditions for effective hydroalkoxylation. In addition to reactions with activated alkenes, IMes catalyzes the formation of vinyl ethers through the 1,4-addition of alcohols to ynones and promotes tandem conjugate addition/Michael cascade reactions. Preliminary data support a Brønsted base mechanism with the free carbene.

| S-EPMC2944903 | biostudies-literature

Iridium-Catalyzed Enantioselective Allylic Substitution of Enol Silanes from Vinylogous Esters and Amides.

Project description:The enol silanes of vinylogous esters and amides are classic dienes for Diels-Alder reactions. Here, we report their reactivity as nucleophiles in Ir-catalyzed, enantioselective allylic substitution reactions. A variety of allylic carbonates react with these nucleophiles to give allylated products in good yields with high enantioselectivities and excellent branched-to-linear ratios. These reactions occur with KF or alkoxide as the additive, but mechanistic studies suggest that these additives do not activate the enol silanes. Instead, they serve as bases to promote the cyclometalation to generate the active Ir catalyst. The carbonate anion, which was generated from the oxidative addition of the allylic carbonate, likely activates the enol silanes to trigger their activity as nucleophiles for reactions with the allyliridium electrophile. The synthetic utility of this method was illustrated by the synthesis of the anti-muscarinic drug, fesoterodine.

| S-EPMC5342901 | biostudies-literature

Copper-Catalyzed Vinylogous Aerobic Oxidation of Unsaturated Compounds with Air.

Project description:A mild and operationally simple copper-catalyzed vinylogous aerobic oxidation of ?,?- and ?,?-unsaturated esters is described. This method features good yields, broad substrate scope, excellent chemo- and regioselectivity, and good functional group tolerance. This method is additionally capable of oxidizing ?,?- and ?,?-unsaturated aldehydes, ketones, amides, nitriles, and sulfones. Furthermore, the present catalytic system is suitable for bisvinylogous and trisvinylogous oxidation. Tetramethylguanidine (TMG) was found to be crucial in its role as a base, but we also speculate that it serves as a ligand to copper(II) triflate to produce the active copper(II) catalyst. Mechanistic experiments conducted suggest a plausible reaction pathway via an allylcopper(II) species. Finally, the breadth of scope and power of this methodology are demonstrated through its application to complex natural product substrates.

| S-EPMC5927363 | 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