scholarly journals Gold-catalyzed intermolecular coupling of sulfonylacetylene with allyl ethers: [3,3]- and [1,3]-rearrangements

2013 ◽  
Vol 9 ◽  
pp. 1724-1729 ◽  
Author(s):  
Jungho Jun ◽  
Hyu-Suk Yeom ◽  
Jun-Hyun An ◽  
Seunghoon Shin
Keyword(s):  
Gold Catalyst ◽  
Sigmatropic Rearrangement ◽  
Allyl Ethers ◽  
Rearrangement Mechanism ◽  
Intermolecular Coupling

Gold-catalyzed intermolecular couplings of sulfonylacetylenes with allyl ethers are reported. A cooperative polarization of alkynes both by a gold catalyst and a sulfonyl substituent resulted in an efficient intermolecular tandem carboalkoxylation. Reactions of linear allyl ethers are consistent with the [3,3]-sigmatropic rearrangement mechanism, while those of branched allyl ethers provided [3,3]- and [1,3]-rearrangement products through the formation of a tight ion–dipole pair.

ChemInform Abstract: (2,3) VS (3,3), THE NOVEL (2,3)SIGMATROPIC REARRANGEMENT OF OXIME-O-ALLYL ETHERS

1973 ◽  
Vol 4 (52) ◽  
pp. no-no
Author(s):  
S. RANGANATHAN ◽  
D. RANGANATHAN ◽  
R. S. SIDHU ◽  
A. K. MEHROTRA
Keyword(s):  
Sigmatropic Rearrangement ◽  
The Novel ◽  
Allyl Ethers

[2,3] [3,3]: the novel [2,3] sigmatropic rearrangement of oxime-o-allyl ethers

1973 ◽  
Vol 14 (37) ◽  
pp. 3577-3578 ◽  
Author(s):  
S. Ranganathan ◽  
D. Ranganathan ◽  
R.S. Sidhu ◽  
A.K. Mehrotra
Keyword(s):  
Sigmatropic Rearrangement ◽  
The Novel ◽  
Allyl Ethers

Electron Holographic Nano-Characterization of Gold Catalyst at Interface

2002 ◽  
Vol 727 ◽  
Author(s):  
S. Ichikawa ◽  
T. Akita ◽  
M. Okumura ◽  
M. Haruta ◽  
K. Tanaka
Keyword(s):  
Contact Angle ◽  
Titanium Oxide ◽  
Gold Catalyst ◽  
Three Dimensional ◽  
High Resolution Electron Microscopy ◽  
Electron Holography ◽  
Gold Particles ◽  
Oxide Support ◽  
The Mean ◽  
A Charge

AbstractThe catalytic properties of nanostructured gold catalyst are known to depend on the size of the gold particles and to be activated when the size decreases to a few nanometers. We investigated the size dependence of the three-dimensional nanostructure on the mean inner potential of gold catalysts supported on titanium oxide using electron holography and high-resolution electron microscopy (HREM). The contact angle of the gold particles on the titanium oxide tended to be over 90° for gold particles with a size of over 5 nm, and below 90° for a size of below 2 nm. This decreasing change in the contact angle (morphology) acts to increase the perimeter and hence the area of the interface between the gold and titanium oxide support, which is considered to be an active site for CO oxidation. The mean inner potential of the gold particles also changed as their size decreased. The value of the inner potential of gold, which is approximately 25 V in bulk state, rose to over 40 V when the size of the gold particles was less than 2 nm. This phenomenon indicates the existence of a charge transfer at the interface between gold and titanium oxide. The 3-D structure change and the inner potential change should be attributed to the specific electronic structure at the interface, owing to both the “nano size effect” and the “hetero-interface effect.”

scholarly journals Fusion genes in gynecologic tumors: the occurrence, molecular mechanism and prospect for therapy

2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Bingfeng Lu ◽  
Ruqi Jiang ◽  
Bumin Xie ◽  
Wu Wu ◽  
Yang Zhao
Keyword(s):  
Tumor Progression ◽  
Massively Parallel Sequencing ◽  
Gynecologic Cancer ◽  
Endometrial Stromal Sarcoma ◽  
Driver Mutations ◽  
Fusion Genes ◽  
Stromal Sarcoma ◽  
Uterine Tumors ◽  
Rearrangement Mechanism ◽  
Gynecologic Tumors

AbstractGene fusions are thought to be driver mutations in multiple cancers and are an important factor for poor patient prognosis. Most of them appear in specific cancers, thus satisfactory strategies can be developed for the precise treatment of these types of cancer. Currently, there are few targeted drugs to treat gynecologic tumors, and patients with gynecologic cancer often have a poor prognosis because of tumor progression or recurrence. With the application of massively parallel sequencing, a large number of fusion genes have been discovered in gynecologic tumors, and some fusions have been confirmed to be involved in the biological process of tumor progression. To this end, the present article reviews the current research status of all confirmed fusion genes in gynecologic tumors, including their rearrangement mechanism and frequency in ovarian cancer, endometrial cancer, endometrial stromal sarcoma, and other types of uterine tumors. We also describe the mechanisms by which fusion genes are generated and their oncogenic mechanism. Finally, we discuss the prospect of fusion genes as therapeutic targets in gynecologic tumors.

scholarly journals Copper-Catalyzed Synthesis of Axially Chiral Biaryls with Diaryliodonium Salts as Arylation Reagents

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3223
Author(s):  
Ji-Wei Zhang ◽  
Shao-Hua Xiang ◽  
Shaoyu Li ◽  
Bin Tan
Keyword(s):  
Amino Alcohols ◽  
Sigmatropic Rearrangement ◽  
Synthetic Route ◽  
Mild Conditions ◽  
Good Substrate ◽  
Diaryliodonium Salts ◽  
Axially Chiral

NOBIN and BINAM derivatives harboring biaryl frameworks are recognized as a class of important atropisomers with versatile applications. Here, we present an efficient synthetic route to access such compounds through copper-catalyzed domino arylation of N-arylhydroxylamines or N-arylhydrazines with diaryliodonium salts and [3,3]-sigmatropic rearrangement. This reaction features mild conditions, good substrate compatibility, and excellent efficiency. The practicality of this protocol was further extended by the synthesis of biaryl amino alcohols.

An Umpolung Oxa-[2,3] Sigmatropic Rearrangement Employing Arynes for the Synthesis of Functionalized Enol Ethers

2021 ◽  
Author(s):  
Rahul N. Gaykar ◽  
Malini George ◽  
Avishek Guin ◽  
Subrata Bhattacharjee ◽  
Akkattu T. Biju
Keyword(s):  
Sigmatropic Rearrangement ◽  
Enol Ethers

scholarly journals Catalytic Activity of Beta-Cyclodextrin-Gold Nanoparticles Network in Hydrogen Evolution Reaction

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 118
Author(s):  
Qui Quach ◽  
Erik Biehler ◽  
Ahmed Elzamzami ◽  
Clay Huff ◽  
Julia M. Long ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Gold Catalyst ◽  
Hydrogen Gas ◽  
Hydrolysis Reaction ◽  
X Ray Diffraction ◽  
Beta Cyclodextrin ◽  
Transmission Electron ◽  
Production Of Hydrogen ◽  
Climate Crisis

The current climate crisis warrants investigation into alternative fuel sources. The hydrolysis reaction of an aqueous hydride precursor, and the subsequent production of hydrogen gas, prove to be a viable option. A network of beta-cyclodextrin capped gold nanoparticles (BCD-AuNP) was synthesized and subsequently characterized by Powder X-Ray Diffraction (P-XRD), Fourier Transform Infrared (FTIR), Transmission Electron Microscopy (TEM), and Ultraviolet-Visible Spectroscopy (UV-VIS) to confirm the presence of gold nanoparticles as well as their size of approximately 8 nm. The catalytic activity of the nanoparticles was tested in the hydrolysis reaction of sodium borohydride. The gold catalyst performed best at 303 K producing 1.377 mL min−1 mLcat−1 of hydrogen. The activation energy of the catalyst was calculated to be 54.7 kJ/mol. The catalyst resisted degradation in reusability trials, continuing to produce hydrogen gas in up to five trials.

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