scholarly journals Metal-Catalyzed Oxidative Coupling of Ketones and Ketone Enolates

Synthesis ◽  
2018 ◽  
Vol 50 (11) ◽  
pp. 2150-2162 ◽  
Author(s):  
Sandip Murarka ◽  
Andrey Antonchick
Keyword(s):  
Oxidative Coupling ◽  
Cross Coupling ◽  
Building Blocks ◽  
Dicarbonyl Compounds ◽  
Carbocyclic Compounds ◽  
Efficient Access ◽  
Ketone Enolates ◽  
Metal Catalyzed

Recent years have witnessed a significant advancement in the field of radical oxidative coupling of ketones towards the synthesis of highly useful synthetic building blocks, such as 1,4-dicarbonyl compounds, and biologically important heterocyclic and carbocyclic compounds. Besides oxidative homo- and cross-coupling of enolates, other powerful methods involving direct C(sp3)–H functionalizations of ketones­ have emerged towards the synthesis of 1,4-dicarbonyl compounds. Moreover, direct α-C–H functionalization of ketones has also allowed an efficient access to carbocycles and heterocycles. This review summarizes all these developments made since 2008 in the field of metal-catalyzed/promoted radical-mediated functionalization of ketones at the α-position.1 Introduction2 Synthesis of 1,4-Dicarbonyl Compounds3 Synthesis of Heterocyclic Scaffolds4 Synthesis of Carbocyclic Scaffolds5 Conclusion

Pyrido[1,2-a]pyrazine - Startprodukte für regioselektive Ringtransformationen und supramolekulare Architekturen / Pyrido[1,2-a]pyrazines - Starting Materials for Regioselective Ringtransformation Reactions and Supramolecular Architectures

2002 ◽  
Vol 57 (4) ◽  
pp. 471-478 ◽  
Author(s):  
D. Müller ◽  
B. Frank ◽  
R. Beckert ◽  
H. Görls
Keyword(s):  
Cycloaddition Reaction ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Building Blocks ◽  
Ring Transformation ◽  
Supramolecular Architectures ◽  
Cross Coupling Reaction ◽  
Metal Catalyzed

The easily available pyrido[1,2-a]pyrazines of type 1 are versatile building blocks for ring transformation reactions.W ith heterocyclic quinones such as quinoline-2,5,8-triones 4a-c, a highly regioselective [4+2]-cycloaddition reaction takes place in the first step, followed by a ring transformation cascade.T he 1,6-diazaanthracene-2,9,10-triones 5a-e, which possess an additional bipyridine substructure, could be isolated as main products.In order to modify the starting products of type 1, a metal-catalyzed cross-coupling reaction with acetylenic benzoic esters 9a,b has been performed.T he modified pyridopyrazines 10a,b which were obtained in good yields could be transformed by analogy to 1a,b into ring-fused heterocyclic quinones 12a,b.

Microwave-assisted Cobalt-copper Dual Catalyzed Ligand Free C-Se Cross-coupling

2020 ◽  
Vol 7 (2) ◽  
pp. 157-163
Author(s):  
Debasish Kundu ◽  
Anup Roy ◽  
Subir Panja ◽  
Raj K. Singh
Keyword(s):  
Transition Metal ◽  
Cross Coupling ◽  
Building Blocks ◽  
Transition Metal Catalysts ◽  
Metal Catalyst ◽  
Co Catalyst ◽  
Ligand Free ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed ◽  
First Time

Background: Organoselenides are important building blocks of several biologically important molecules and natural products. Several protocols have been developed by chemists for their synthesis. Transition metal-catalyzed cross-coupling is a powerful tool for this purpose in the last two decades. Various transition metal catalysts e.g. Pd, Ni, Cu, In etc. have been used for performing C-Se cross-coupling in the presence or absence of ligands. Objective: Development of a sustainable protocol for transition metal-catalyzed C-Se cross-coupling is the main objective of this research. Recently, Cobalt has been applied as a cheap and sustainable transition metal catalyst in several organic reactions. This protocol is focused on applying cobalt salt as a catalyst for performing C-Se cross-coupling for the first time. Methods: Co(acac)2 has been successfully employed for performing Se-arylations in the presence of CuI, which acts as a co-catalyst under microwave irradiation. NMP was used as solvent and KOH as a reductant in this reaction. Results: Both iodo-and bromoarenes have been used to perform C-Se cross-coupling with diaryl diselenide under this Co/Cu dual catalytic system. The reaction was successful with both electrondonating and withdrawing groups in ortho-, meta-, and para-positions in the aromatic ring of Bromo and iodoarenes. Conclusion: This is an effective protocol for the preparation of organoselenides, catalyzed by cobalt in the presence of copper. The mechanism has been established by several experimental techniques.

scholarly journals Catalytic Hydrofunctionalization Reactions of 1,3-Diynes

Catalysts ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 89
Author(s):  
Victorio Cadierno
Keyword(s):  
Organic Chemistry ◽  
Triple Bond ◽  
Building Blocks ◽  
Review Article ◽  
Addition Reactions ◽  
Synthetic Organic Chemistry ◽  
Carbocyclic Compounds ◽  
Metal Catalyzed

Metal-catalyzed hydrofunctionalization reactions of alkynes, i.e., the addition of Y–H units (Y = heteroatom or carbon) across the carbon–carbon triple bond, have attracted enormous attention for decades since they allow the straightforward and atom-economic access to a wide variety of functionalized olefins and, in its intramolecular version, to relevant heterocyclic and carbocyclic compounds. Despite conjugated 1,3-diynes being considered key building blocks in synthetic organic chemistry, this particular class of alkynes has been much less employed in hydrofunctionalization reactions when compared to terminal or internal monoynes. The presence of two C≡C bonds in conjugated 1,3-diynes adds to the classical regio- and stereocontrol issues associated with the alkyne hydrofunctionalization processes’ other problems, such as the possibility to undergo 1,2-, 3,4-, or 1,4-monoadditions as well as double addition reactions, thus increasing the number of potential products that can be formed. In this review article, metal-catalyzed hydrofunctionalization reactions of these challenging substrates are comprehensively discussed.

scholarly journals Ligand-Controlled Regiodivergent Palladium-Catalyzed Hydrogermylation of Ynamides

2020 ◽  
Author(s):  
Vincent Debrauwer ◽  
Aneta Turlik ◽  
Lénaïc Rummler ◽  
Alessandro Prescimone ◽  
Nicolas Blanchard ◽  
...  
Keyword(s):  
Small Molecules ◽  
Functional Group ◽  
Cross Coupling ◽  
Building Blocks ◽  
Coupling Reactions ◽  
Heterocyclic Chemistry ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
Metal Catalyzed ◽  
Pi System

Ynamides are fascinating small molecules with complementary reactivities under radical, ionic and metal-catalyzed conditions. We report herein synthetic and DFT investigations of palladium-catalyzed ligand-controlled regiodivergent hydro-metallation reactions of ynamides. Germylated and stannylated enamides are obtained with excellent alpha,<i>E</i>- or beta,<i>E</i>-selectivities and a broad functional group tolerance. Such a regiodivergent palladium-catalyzed process is unique in ynamide chemistry and allows for the elaboration of metallated-enamides that are useful building blocks for cross-coupling reactions or heterocyclic chemistry. DFT calculations fully support the experimental data and demonstrate the crucial roles of the <i>trans</i>-geometry of the [H-Pd(L)-Ge] complex, as well as of the steric requirements of the phosphine ligand. In addition, the prevalence of a hydro-palladation pathway over a metal-palladation of the pi system of the ynamide was demonstrated.

scholarly journals EMI Series Ruthenium-catalysed oxidative coupling of vinyl derivatives and application in tandem hydrogenation

2021 ◽  
Author(s):  
Naba Abuhafez ◽  
Hervé Ruffin ◽  
Raghu Kamaraj ◽  
Christian Bruneau ◽  
Rafael Gramage-Doria
Keyword(s):  
Catalytic System ◽  
Oxidative Coupling ◽  
Cross Coupling ◽  
Building Blocks ◽  
Vinyl Derivatives

The first ruthenium-catalyzed oxidative homo- and cross-coupling of exclusive vinyl derivatives giving highly valued 1,3-diene building blocks is reported. The catalytic system is based on readily available reagents and it...

scholarly journals Ligand-Controlled Regiodivergent Palladium-Catalyzed Hydrogermylation of Ynamides

2020 ◽  
Author(s):  
Vincent Debrauwer ◽  
Aneta Turlik ◽  
Lénaïc Rummler ◽  
Alessandro Prescimone ◽  
Nicolas Blanchard ◽  
...  
Keyword(s):  
Small Molecules ◽  
Functional Group ◽  
Cross Coupling ◽  
Building Blocks ◽  
Coupling Reactions ◽  
Heterocyclic Chemistry ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
Metal Catalyzed ◽  
Pi System

Ynamides are fascinating small molecules with complementary reactivities under radical, ionic and metal-catalyzed conditions. We report herein synthetic and DFT investigations of palladium-catalyzed ligand-controlled regiodivergent hydro-metallation reactions of ynamides. Germylated and stannylated enamides are obtained with excellent alpha,<i>E</i>- or beta,<i>E</i>-selectivities and a broad functional group tolerance. Such a regiodivergent palladium-catalyzed process is unique in ynamide chemistry and allows for the elaboration of metallated-enamides that are useful building blocks for cross-coupling reactions or heterocyclic chemistry. DFT calculations fully support the experimental data and demonstrate the crucial roles of the <i>trans</i>-geometry of the [H-Pd(L)-Ge] complex, as well as of the steric requirements of the phosphine ligand. In addition, the prevalence of a hydro-palladation pathway over a metal-palladation of the pi system of the ynamide was demonstrated.

Concise Synthesis of GB22 by Endo-Selective Siloxycyclopropane Arylation

2019 ◽  
Author(s):  
Hannah E. Burdge ◽  
Takuya Oguma ◽  
Takahiro Kawajiri ◽  
Ryan Shenvi
Keyword(s):  
Intramolecular Cyclization ◽  
Cross Coupling ◽  
Building Blocks ◽  
Ring Expansion ◽  
Dual Catalysis ◽  
Acid Labile

<div><div><div><p>The first synthesis of GB22 was accomplished by a con- cise, modular route. Two building blocks converged in a novel sp3-sp2 attached-ring coupling that used Ir/Ni dual-catalysis to reverse the regioselectivity of siloxycy- clopropane arylation. This cross-coupling proved general to access β-substituted tetralones via ring-expansion of indanone-derived siloxycyclopropanes. The congested, bridging rings of the GB alkaloids were completed using an aluminum-HFIP complex that effected intramolecular cyclization of an acid-labile substrate.</p></div></div></div>

Concise Synthesis of GB22 by Endo-Selective Siloxycyclopropane Arylation

2019 ◽  
Author(s):  
Hannah E. Burdge ◽  
Takuya Oguma ◽  
Takahiro Kawajiri ◽  
Ryan Shenvi
Keyword(s):  
Intramolecular Cyclization ◽  
Cross Coupling ◽  
Building Blocks ◽  
Ring Expansion ◽  
Dual Catalysis ◽  
Acid Labile

<div><div><div><p>The first synthesis of GB22 was accomplished by a con- cise, modular route. Two building blocks converged in a novel sp3-sp2 attached-ring coupling that used Ir/Ni dual-catalysis to reverse the regioselectivity of siloxycy- clopropane arylation. This cross-coupling proved general to access β-substituted tetralones via ring-expansion of indanone-derived siloxycyclopropanes. The congested, bridging rings of the GB alkaloids were completed using an aluminum-HFIP complex that effected intramolecular cyclization of an acid-labile substrate.</p></div></div></div>

Modular, Stereocontrolled Cβ–H/Cα–C Activation of Alkyl Carboxylic Acids

2019 ◽  
Author(s):  
Ming Shang ◽  
Karla S. Feu ◽  
Julien C. Vantourout ◽  
Lisa M. Barton ◽  
Heather L. Osswald ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Heterocyclic Compounds ◽  
Cross Coupling ◽  
Building Blocks ◽  
Enantioselective Synthesis ◽  
Carbon Centers ◽  
Drug Candidates ◽  
Rapid Diversification ◽  
Directing Group ◽  
Compound Series

<div> <div> <div> <p>The union of two powerful transformations, directed C–H activation and decarboxylative cross-coupling, for the enantioselective synthesis of vicinally functionalized alkyl, carbocyclic, and heterocyclic compounds is described. Starting from simple carboxylic acid building blocks, this modular sequence exploits the residual directing group to access more than 50 scaffolds that would be otherwise extremely difficult to prepare. The tactical use of these two transformations accomplishes a formal vicinal difunctionalization of carbon centers in a way that is modular and thus amenable to rapid diversity incorporation. A simplification of routes to known preclinical drug candidates is presented along with the rapid diversification of an antimalarial compound series. </p> </div> </div> </div>

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