scholarly journals Cross-coupling of dissimilar ketone enolates via enolonium species to afford non-symmetrical 1,4-diketones

2018 ◽  
Vol 14 ◽  
pp. 992-997 ◽  
Author(s):  
Keshaba N Parida ◽  
Gulab K Pathe ◽  
Shimon Maksymenko ◽  
Alex M Szpilman
Keyword(s):  
Organic Synthesis ◽  
Cross Coupling ◽  
Enol Ether ◽  
Enol Ethers ◽  
Ketone Enolates ◽  
The Cross

Due to their closely matched reactivity, the coupling of two dissimilar ketone enolates to form a 1,4-diketone remains a challenge in organic synthesis. We herein report that umpolung of a ketone trimethylsilyl enol ether (1 equiv) to form a discrete enolonium species, followed by addition of as little as 1.2–1.4 equivalents of a second trimethylsilyl enol ether, provides an attractive solution to this problem. A wide array of enolates may be used to form the 1,4-diketone products in 38 to 74% yield. Due to the use of two TMS enol ethers as precursors, an optimization of the cross-coupling should include investigating the order of addition.

scholarly journals Iron-Catalyzed C(sp2)–C(sp3) Cross-Coupling of Aryl Chlorobenzoates with Alkyl Grignard Reagents

Molecules ◽  
2020 ◽  
Vol 25 (1) ◽  
pp. 230 ◽  
Author(s):  
Elwira Bisz ◽  
Michal Szostak
Keyword(s):  
Organic Synthesis ◽  
Nucleophilic Addition ◽  
Functional Group ◽  
High Selectivity ◽  
Cross Coupling ◽  
Environmentally Benign ◽  
Grignard Reagents ◽  
High Importance ◽  
Iron Salts ◽  
The Cross

Aryl benzoates are compounds of high importance in organic synthesis. Herein, we report the iron-catalyzed C(sp2)–C(sp3) Kumada cross-coupling of aryl chlorobenzoates with alkyl Grignard reagents. The method is characterized by the use of environmentally benign and sustainable iron salts for cross-coupling in the catalytic system, employing benign urea ligands in the place of reprotoxic NMP (NMP = N-methyl-2-pyrrolidone). It is notable that high selectivity for the cross-coupling is achieved in the presence of hydrolytically-labile and prone to nucleophilic addition phenolic ester C(acyl)–O bonds. The reaction provides access to alkyl-functionalized aryl benzoates. The examination of various O-coordinating ligands demonstrates the high activity of urea ligands in promoting the cross-coupling versus nucleophilic addition to the ester C(acyl)–O bond. The method showcases the functional group tolerance of iron-catalyzed Kumada cross-couplings.

scholarly journals Suzuki–Miyaura cross coupling is not an informative reaction to demonstrate the performance of new solvents

2020 ◽  
Vol 16 ◽  
pp. 1001-1005
Author(s):  
James Sherwood
Keyword(s):  
Organic Synthesis ◽  
Propylene Carbonate ◽  
Cross Coupling ◽  
Ethyl Lactate ◽  
Limited Information ◽  
The Cross

The development and study of new solvents has become important due to a proliferation of regulations preventing or limiting the use of many conventional solvents. In this work, the suitability of the Suzuki–Miyaura reaction to demonstrate the usefulness of new solvents was evaluated, including Cyrene™, dimethyl isosorbide, ethyl lactate, 2-methyltetrahydrofuran (2-MeTHF), propylene carbonate, and γ-valerolactone (GVL). It was found that the cross coupling is often unaffected by the choice of solvent, and therefore the Suzuki–Miyaura reaction provides limited information regarding the usefulness of any particular solvent for organic synthesis.

Addition of Allylsilanes and Silyl Enol Ethers to Small Oxygenated Rings: New Tools for Organic Synthesis

2014 ◽  
Vol 18 (5) ◽  
pp. 525-546 ◽  
Author(s):  
Carmen Hernandez-Cervantes ◽  
Miriam Alvarez-Corral ◽  
Manuel Munoz-Dorado ◽  
Ignacio Rodriguez-Garcia
Keyword(s):  
Organic Synthesis ◽  
Enol Ethers ◽  
Silyl Enol Ethers

Microwave Assisted Organic Synthesis: Cross Coupling and Multicomponent Reactions

2013 ◽  
Vol 17 (5) ◽  
pp. 474-490 ◽  
Author(s):  
Amit Kumar Gupta ◽  
Neetu Singh ◽  
Krishna Nand Singh
Keyword(s):  
Organic Synthesis ◽  
Multicomponent Reactions ◽  
Cross Coupling ◽  
Microwave Assisted

Recent Advances in C–Br Bond Formation

Synlett ◽  
2021 ◽  
Author(s):  
Ying-Yeung Yeung ◽  
Jonathan Wong
Keyword(s):  
Organic Synthesis ◽  
Aromatic Compounds ◽  
Bond Formation ◽  
Cross Coupling ◽  
Catalytic Site ◽  
Atom Transfer ◽  
Bond Forming ◽  
Recent Advances ◽  
Catalytic Asymmetric ◽  
Site Selective

AbstractOrganobromine compounds are extremely useful in organic synthesis. In this perspective, a focused discussion on some recent advancements in C–Br bond-forming reactions is presented.1 Introduction2 Selected Recent Advances2.1 Catalytic Asymmetric Bromopolycyclization of Olefinic Substrates2.2 Catalytic Asymmetric Intermolecular Bromination2.3 Some New Catalysts and Reagents for Bromination2.4 Catalytic Site-Selective Bromination of Aromatic Compounds2.5 sp3 C–H Bromination via Atom Transfer/Cross-Coupling3 Outlook

A horizontal linear vibrator for measuring the cross-coupling coefficient of superconducting gravity gradiometers

Measurement ◽  
2021 ◽  
Vol 174 ◽  
pp. 109083
Author(s):  
Lu Zhang ◽  
Yuntao Qiu ◽  
Xikai Liu ◽  
Liang Chen ◽  
Ning Zhang ◽  
...  
Keyword(s):  
Coupling Coefficient ◽  
Cross Coupling ◽  
Superconducting Gravity ◽  
The Cross

scholarly journals Divergent Pathways Regulate Ligand-Independent Activation of ERα in SK-N-BE Neuroblastoma and COS-1 Renal Carcinoma Cells

1998 ◽  
Vol 12 (6) ◽  
pp. 835-841
Author(s):  
Cesare Patrone ◽  
Elisabetta Gianazza ◽  
Sabrina Santagati ◽  
Paola Agrati ◽  
Adriana Maggi
Keyword(s):  
Cell Line ◽  
Intracellular Signaling ◽  
Steroid Receptors ◽  
Neuroblastoma Cell ◽  
Cross Coupling ◽  
Activation Function ◽  
Neuroblastoma Cell Line ◽  
Membrane Receptors ◽  
Insulin Dependent ◽  
The Cross

Abstract The α-estrogen receptor (ERα) transcriptional activity can be regulated either by binding to the cognate ligand or by intracellular signaling pathways responsive to a variety of factors acting through cell membrane receptors. Studies carried out in HeLa and COS-1 cells demonstrated that the cross-coupling between estrogen and growth factor receptors is mediated by p21ras and requires phosphorylation of a specific serine residue (Ser 118 in the human ERα and Ser 122 in mouse ERα) located in the ERα N-terminal activation function 1 (AF-1). Likewise, in the SK-N-BE neuroblastoma cell line p21ras is involved in the cross-coupling between insulin and ERα receptors. However, in this cell line Ser 122 is not necessary for insulin-dependent activation of unliganded ERα. In addition, after insulin activation, the electrophoretic mobility associated to serine hyperphosphorylation of ERα in SK-N-BE and in COS-1 cells is different. Our study rules out the possibility of tyrosine phosporylation in unliganded ERα activation by means of transactivation studies of ERα tyrosine mutants and analysis of Tyr phosphorylation immunoreactivity. The two cofactors for steroid receptors RIP 140 and SRC-1 do not seem to be specifically involved in the insulin-induced ERα transactivation. The present study demonstrates the possibility of an alternative, cell-specific pathway of cross-coupling between intracellular and membrane receptors, which might be of importance for the understanding of the physiological significance of this mode of activation in the nervous system.

Sign in / Sign up

Export Citation Format

Share Document