scholarly journals A general metal-free approach for the stereoselective synthesis of C-glycals from unactivated alkynes

2014 ◽  
Vol 10 ◽  
pp. 2649-2653 ◽  
Author(s):  
Shekaraiah Devari ◽  
Manjeet Kumar ◽  
Ramesh Deshidi ◽  
Masood Rizvi ◽  
Bhahwal Ali Shah
Keyword(s):  
Stereoselective Synthesis ◽  
Single Step ◽  
Metal Free

A novel metal-free strategy for a rapid and α-selctive C-alkynylation of glycals was developed. The reaction utilizes TMSOTf as a promoter to generate in situ trimethylsilylacetylene for C-alkynylation. Thanks to this methodology, we can access C-glycosides in a single step from a variety of acetylenes , i.e., arylacetylenes and most importantly aliphatic alkynes.

A Metal-free and β-Stereoselective Synthesis of 2-Deoxy-C-aryl Glycosides: Synthesis of 5-aza analogues of Aquayamycin

Synlett ◽  
2021 ◽  
Author(s):  
Yuling Mei ◽  
nan jiang ◽  
Yu Yang ◽  
Wan Zhang ◽  
Saifeng Qiu ◽  
...  
Keyword(s):  
Stereoselective Synthesis ◽  
Metal Free ◽  
Wide Range ◽  
One Step ◽  
Aryl Glycosides ◽  
Aryl Glycoside

A convenient protocol for β-stereoselective synthesis of 2-deoxy-C-aryl glycosides has been developed. This reaction takes place in one step by using I2/Et3SiH to activate glycosyl acetate to generate glycosyl iodide intermediate in situ, which was captured by naphthol followed by Fries-like O- → C-glycoside rearrangement to selectively afford β-C-aryl glycoside. The approach is applicable to a wide range of naphthol modules, and its utility was demonstrated in the synthesis of 5-aza analogues of Aquayamycin.

Acetic acid promoted tandem cyclization of in situ generated 1,3-dipoles: stereoselective synthesis of dispiroimidazolidinyl and dispiropyrrolidinyl oxindoles with multiple chiral stereocenters

RSC Advances ◽  
2015 ◽  
Vol 5 (97) ◽  
pp. 79413-79422 ◽  
Author(s):  
Koorathota Suman ◽  
Sathiah Thennarasu
Keyword(s):  
Acetic Acid ◽  
Stereoselective Synthesis ◽  
Single Step ◽  
Pyrrolidine Ring ◽  
Acid Catalyzed ◽  
Chiral Centers ◽  
Tandem Cyclization

Acetic acid catalyzed in situ generation of ketimine based 1,3-dipoles, and single-step construction of imidazolidine ring with three chiral centers and pyrrolidine ring with four chiral centers via formation of new C–N and C–C bonds is reported.

Stereoselective synthesis of alkyl styryl selenides in one-pot: a straightforward approach by in situ dialkyl diselenide formation under transition metal-free conditions

RSC Advances ◽  
2015 ◽  
Vol 5 (128) ◽  
pp. 105699-105706 ◽  
Author(s):  
Adrián A. Heredia ◽  
Alicia B. Peñéñory
Keyword(s):  
Transition Metal ◽  
Stereoselective Synthesis ◽  
One Pot ◽  
Metal Free ◽  
One Pot Synthesis ◽  
Straightforward Approach

One-pot synthesis of alkyl styryl selenides using KSeCN as selenium source.

scholarly journals Single Step In Situ Detection of Surface Protein and MicroRNA in Clustered Extracellular Vesicles Using Flow Cytometry

2021 ◽  
Vol 10 (2) ◽  
pp. 319
Author(s):  
Hee Cheol Yang ◽  
Won Jong Rhee
Keyword(s):  
Extracellular Vesicles ◽  
Liquid Biopsy ◽  
Molecular Beacon ◽  
Disease Diagnosis ◽  
Single Step ◽  
Flow Cytometer ◽  
Surface Proteins ◽  
Biomarker Detection ◽  
In Situ Detection

Because cancers are heterogeneous, it is evident that multiplexed detection is required to achieve disease diagnosis with high accuracy and specificity. Extracellular vesicles (EVs) have been a subject of great interest as sources of novel biomarkers for cancer liquid biopsy. However, EVs are nano-sized particles that are difficult to handle; thus, it is necessary to develop a method that enables efficient and straightforward EV biomarker detection. In the present study, we developed a method for single step in situ detection of EV surface proteins and inner miRNAs simultaneously using a flow cytometer. CD63 antibody and molecular beacon-21 were investigated for multiplexed biomarker detection in normal and cancer EVs. A phospholipid-polymer-phospholipid conjugate was introduced to induce clustering of the EVs analyzed using nanoparticle tracking analysis, which enhanced the detection signals. As a result, the method could detect and distinguish cancer cell-derived EVs using a flow cytometer. Thus, single step in situ detection of multiple EV biomarkers using a flow cytometer can be applied as a simple, labor- and time-saving, non-invasive liquid biopsy for the diagnosis of various diseases, including cancer.

scholarly journals Converting copper sulfide to copper with surface sulfur for electrocatalytic alkyne semi-hydrogenation with water

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yongmeng Wu ◽  
Cuibo Liu ◽  
Changhong Wang ◽  
Yifu Yu ◽  
Yanmei Shi ◽  
...  
Keyword(s):  
Binding Energy ◽  
Noble Metal ◽  
Atomic Hydrogen ◽  
Copper Sulfide ◽  
Low Cost ◽  
Water Electrolysis ◽  
Metal Free ◽  
Copper Nanowire

AbstractElectrocatalytic alkyne semi-hydrogenation to alkenes with water as the hydrogen source using a low-cost noble-metal-free catalyst is highly desirable but challenging because of their over-hydrogenation to undesired alkanes. Here, we propose that an ideal catalyst should have the appropriate binding energy with active atomic hydrogen (H*) from water electrolysis and a weaker adsorption with an alkene, thus promoting alkyne semi-hydrogenation and avoiding over-hydrogenation. So, surface sulfur-doped and -adsorbed low-coordinated copper nanowire sponges are designedly synthesized via in situ electroreduction of copper sulfide and enable electrocatalytic alkyne semi-hydrogenation with over 99% selectivity using water as the hydrogen source, outperforming a copper counterpart without surface sulfur. Sulfur anion-hydrated cation (S2−-K+(H2O)n) networks between the surface adsorbed S2− and K+ in the KOH electrolyte boost the production of active H* from water electrolysis. And the trace doping of sulfur weakens the alkene adsorption, avoiding over-hydrogenation. Our catalyst also shows wide substrate scopes, up to 99% alkenes selectivity, good reducible groups compatibility, and easily synthesized deuterated alkenes, highlighting the promising potential of this method.

In situ construction of phenanthroline-based cationic radical porous hybrid polymers for metal-free heterogeneous catalysis

2021 ◽  
Vol 9 (12) ◽  
pp. 7556-7565
Author(s):  
Guojian Chen ◽  
Yadong Zhang ◽  
Ke Liu ◽  
Xiaoqing Liu ◽  
Lei Wu ◽  
...  
Keyword(s):  
Heterogeneous Catalysis ◽  
Heterogeneous Catalysts ◽  
Hybrid Polymers ◽  
Metal Free ◽  
Oxidation Of Sulfides

Constructing phenanthroline-based cationic radical porous hybrid polymers as versatile metal-free heterogeneous catalysts for both oxidation of sulfides and CO2 conversion.

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