Browse
Submit Data
Databases
API
Help

Dataset Information

29 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

An alkoxide-directed alkyne-allene cross-coupling for stereoselective synthesis of 1,4-dienes.

ABSTRACT: A titanium alkoxide-mediated convergent coupling between internal alkynes and allenes is described for the regio- and stereocontrolled synthesis of substituted acyclic 1,4-dienes.

SUBMITTER: Shimp HL

PROVIDER: S-EPMC4319186 | biostudies-literature | 2007 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

An alkoxide-directed alkyne-allene cross-coupling for stereoselective synthesis of 1,4-dienes.

Shimp Heidi L HL Micalizio Glenn C GC

Chemical communications (Cambridge, England) 20070823 43

A titanium alkoxide-mediated convergent coupling between internal alkynes and allenes is described for the regio- and stereocontrolled synthesis of substituted acyclic 1,4-dienes. ...[more]

PMID: 17971979

Similar Datasets

Allene-alkyne cross-coupling for stereoselective synthesis of substituted 1,4-dienes and cross-conjugated trienes.

Project description:Titanium-mediated cross-coupling of allenic alcohols with alkynes has been investigated. Divergent reaction pathways were discovered that provide either stereodefined 1,4-dienes or substituted cross-conjugated trienes. In short, allene substitution plays a critical role in the determination of reaction pathway.

| S-EPMC2577592 | biostudies-literature

Synthesis of the Cortistatin Pentacyclic Core by Alkoxide-Directed Metallacycle-Mediated Annulative Cross-Coupling.

Project description:The pentacyclic core skeleton of the cortistatins has been prepared in a stereoselective fashion by strategic use of an alkoxide-directed metallacycle-mediated annulative cross-coupling. This metal-centered tandem reaction delivers a polyunsaturated hydrindane and establishes the C13 stereodefined quaternary center with high levels of stereocontrol. Subsequent regio- and stereoselective global hydroboration results in the realization of the DE-trans ring fusion and a tertiary alcohol at C8. Establishment of the ABC-tricyclic subunit was then accomplished through phenolic oxidation/trans-acetalization, chemoselective reduction, regioselective cleavage, and intramolecular alkylation at C5.

| S-EPMC4892975 | biostudies-literature

1-(Triethoxysilyl)buta-1,3-dienes-New Building Blocks for Stereoselective Synthesis of Unsymmetrical (E,E)-1,4-Disubstituted 1,3-dienes.

Project description:A convenient methodology for the highly stereoselective synthesis of unsymmetrical (1E,3E)-1,4-disubstituted 1,3-dienes based on palladium-catalyzed Hiyama cross-coupling reaction of 1-(triethoxysilyl)-substituted buta-1,3-dienes with aryl iodides is reported.

| S-EPMC5458880 | biostudies-other

NHC-Ni catalyzed enantioselective synthesis of 1,4-dienes by cross-hydroalkenylation of cyclic 1,3-dienes and heterosubstituted terminal olefins.

Project description:Enantioenriched 1,4-dienes are versatile building blocks in asymmetric synthesis, therefore their efficient synthesis directly from chemical feedstock is highly sought after. Here, we show an enantioselective cross-hydroalkenylation of cyclic 1,3-diene and hetero-substituted terminal olefin by using a chiral [NHC-Ni(allyl)]BArF catalyst. Using a structurally flexible chiral C2 NHC-Ni design is key to access a broad scope of chiral 1,4-diene 3 or 3' with high enantioselectivity. This study also offers insights on how to regulate chiral C2 NHC-Ni(II) 1,3-allylic shift on cyclic diene 1 and to build sterically more hindered endocyclic chiral allylic structures on demand.

| S-EPMC7210895 | biostudies-literature

Stereoselective synthesis of pentasubstituted 1,3-dienes <i>via</i> Ni-catalyzed reductive coupling of unsymmetrical internal alkynes.

Project description:The reductive coupling of alkynes represents a powerful strategy for the rapid synthesis of highly substituted 1,3-dienes. This method has the advantages of high atom and step economy, and readily available substrates. Unfortunately, the intermolecular coupling of unsymmetrical internal alkynes remains extremely challenging due to the difficulty in controlling self-dimerization and cross-coupling, as well as stereo- and regioselectivity. Previous reports are still limited to intramolecular processes or the use of stoichiometric amounts of metal catalyst. Herein, we report that nickel-catalyzed reductive coupling of two unsymmetrical internal alkynes can overcome the above-mentioned limitations by using a hemilabile directing group strategy to control the regioselectivity. A series of synthetically challenging penta-substituted 1,3-dienes are obtained in good yields with high regio- and enantioselectivity (mostly > 20/1 rr, >90% ee).

| S-EPMC8162379 | biostudies-literature

Regioselective allene hydroarylation via one-pot allene hydrosilylation/Pd-catalyzed cross-coupling.

Project description:Advances in hydroarylation have been achieved by the development of a one-pot regioselective allene hydrosilylation/Pd(0)-catalyzed cross-coupling protocol. The regioselectivity is primarily governed by N-heterocyclic carbene (NHC) ligand identity in the hydrosilylation step and is preserved in the subsequent cross-coupling reaction. This methodology affords streamlined access to functionalized 1,1-disubstituted alkenes with excellent regiocontrol.

| S-EPMC4201326 | biostudies-literature

Total synthesis of lehualide B by allylic alcohol-alkyne reductive cross-coupling.

Project description:The total synthesis of anticancer marine natural product lehualide B is described. Overall, the synthesis proceeds in just eight steps from a simple gamma-pyrone, does not require the use of protecting groups, and delivers each nonconjugated trisubstituted alkene with high levels of stereoselection. The challenging C12-C16 bis-trisubstituted 1,4-diene was installed with a complex reductive cross-coupling reaction between a preformed Ti-alkyne complex and a pyrone-containing allylic alcohol.

| S-EPMC2923668 | biostudies-other

Acceleration of metallacycle-mediated alkyne-alkyne cross-coupling with TMSCl.

Project description:Investigation of titanium-centered metallacycle-mediated cross-coupling between unsymmetrical internal alkynes has led to the discovery that TMSCl significantly accelerates the C-C bond forming event. We report a collection of results that compare the efficiency of this reaction employing Ti(Oi-Pr)4/2n-BuLi in PhMe with and without TMSCl, demonstrating in every case that the presence of TMSCl has a profound impact on efficiency. While relevant in the context of developing this fundamental bond-forming process as an entry to more complex organometallic transformations, these modified reaction conditions allow coupling processes to be run at > 10 times the concentrations previously possible [in 2.4M n-BuLi (hexanes)], without the requirement of additional solvent. Finally, we demonstrate the effectiveness of these modified reaction conditions for the annulative cross-coupling between TMS-alkynes and 1,6-enynes leading to the formation of angularly substituted hydrindanes with, now well appreciated, high levels of regio- and stereoselection.

| S-EPMC5046837 | biostudies-literature

Regio- and Stereoselective Allylindation of Alkynes Using InBr? and Allylic Silanes: Synthesis, Characterization, and Application of 1,4-Dienylindiums toward Skipped Dienes.

Project description:Regioselective anti-allylindation of alkynes was achieved using InBr? and allylic silanes. Various types of alkynes and allylic silanes were applicable to the present allylindation. This sequential process used the generated 1,4-dienylindiums to establish novel synthetic methods for skipped dienes. The 1,4-dienylindiums were characterized by spectral analysis and treated with I? to stereoselectively give 1-iodo-1,4-dienes. The Pd-catalyzed cross coupling of 1,4-dienylindium with iodobenzene successfully proceeded in a one-pot manner to afford the corresponding 1-aryl-1,4-diene.

| S-EPMC6222668 | biostudies-literature

Synthesis of Highly Oxygenated Carbocycles by Stereoselective Coupling of Alkynes to 1,3- and 1,4-Dicarbonyl Systems.

Project description:Densely substituted and highly oxygenated carbocycles are challenging targets for synthesis. In particular, those possessing numerous contiguous, fully substituted carbon atoms (i.e., tertiary alcohols and quaternary centers) are often not accessible in a direct fashion, necessitating the strategic decoupling of ring-formation from the establishment of functionality about the system. Here, we describe an approach to the construction of highly oxygenated mono-, di-, and polycyclic carbocycles from the reaction of disubstituted alkynes with ?- or ?-dicarbonyl systems. These processes embrace a variant of metallacycle-mediated annulation chemistry where initial alkyne-carbonyl coupling is followed by a second, now intramolecular, stereoselective C-C bond-forming event. In addition to revealing the basic reactivity pattern in intermolecular settings, we demonstrate that this class of reactivity is quite powerful in a fully intramolecular context and, when terminated by a stereoselective oxidation process, can be used to generate polycyclic systems containing a fully substituted and highly oxygenated five-membered ring.

| S-EPMC5600187 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

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