ChemInform Abstract: Metal-Free Catalytic Cascade to Chromones: Direct Coupling of Salicylaldehydes and Activated Alkynes Triggered by Aryloxyl Radicals.

ChemInform ◽  
2016 ◽  
Vol 47 (18) ◽  
Author(s):  
Ping Wang ◽  
Zhongfeng Li ◽  
Shengli Cao ◽  
Honghua Rao
RSC Advances ◽  
2015 ◽  
Vol 5 (129) ◽  
pp. 106350-106354 ◽  
Author(s):  
Ping Wang ◽  
Zhongfeng Li ◽  
Shengli Cao ◽  
Honghua Rao

The first intermolecular addition reaction of aryloxyl radicals to CC bonds was disclosed, which can afford biologically important chromonsviaa PhNMe3I-catalyzed direct coupling of salicylaldehydes and activated internal alkynes in only one step.


2021 ◽  
Author(s):  
Ting Han ◽  
Shusheng Chen ◽  
Xinnan Wang ◽  
Xinyao Fu ◽  
Haifei Wen ◽  
...  

The development of autonomous materials with desired performance and built-in visualizable sensing units is of great academic and industrial significance. Although a wide range of damage indication methods have been reported, the “turn-on” sensing mechanism by damaging events based on microcapsule systems, especially those relying on chemical reactions to elicit a chromogenic response, are still very limited. Herein, a facile and metal-free polymerization route with an interesting reaction-induced coloration effect is demonstrated. Under the catalysis of 1,4-diazabicyclo[2.2.2]octane (DABCO), the polymerizations of difunctional or trifunctional activated alkynes proceed very quickly at 0 oC in air. A series of polymers composed of stereoregular enyne structure (major unit) and divinyl ether structure (minor unit) are obtained. Both the catalyst and monomers are colorless while the polymerized products are deep-colored. This process can be applied for the damage visualization of polymers using the microencapsulation technique. Microcapsules containing the reactive alkyne monomer are prepared and mixed in a DABCO-dispersed polymer film. The mechanical damage of this composite film can be readily visualized once the reaction is initiated from the ruptured microcapsules. Moreover, the newly formed polymer automatically sealed the cracks with an additional protection function.


2014 ◽  
Vol 86 (3) ◽  
pp. 329-333 ◽  
Author(s):  
Sébastien Lemaire ◽  
Amandine Xolin ◽  
Charlotte Gozlan ◽  
Vittorio Farina

Abstract Were are reporting a highly diastereoselective, transition-metal-free approach of C-aryl glycosides in the pyranoside and furanoside series by the direct coupling of glycosyl halides with diarylzinc reagents in a toluene/di-n-butyl ether solvent mixture.


2016 ◽  
Vol 52 (15) ◽  
pp. 3175-3178 ◽  
Author(s):  
Tao Miao ◽  
Dong Xia ◽  
Yang Li ◽  
Pinhua Li ◽  
Lei Wang

The oxidative difunctionalization of aryl alkynoatesviaa tandem oxidative benzylation/1,4-aryl migration/decarboxylation to trisubstituted alkenes was developed under metal-free conditions.


Synthesis ◽  
2018 ◽  
Vol 50 (08) ◽  
pp. 1728-1736 ◽  
Author(s):  
Tingting Liu ◽  
Zhaohong Liu ◽  
Zhenhua Liu ◽  
Donghua Hu ◽  
Yeming Wang

An efficient and transition-metal-free protocol for the synthesis of (Z)-N-arylnitrones from the direct coupling of N-nosylhydrazones with nitrosoarenes under mild conditions is described. The protocol is compatible with a wide range of functional groups placed on both the reagents and provided the corresponding nitrones in good to excellent yields by simple recrystallization process. The use of these 1,3-dipoles for the synthesis of substituted indoles is elaborated for 2,3-diphenyl-1H-indole.


Research ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Xianglong Hu ◽  
Xueqian Zhao ◽  
Benzhao He ◽  
Zheng Zhao ◽  
Zheng Zheng ◽  
...  

The efficient bioconjugation of functional groups/molecules to targeted matrix and bio-related species drives the great development of material science and biomedicine, while the dilemma of metal catalysis, uneasy premodification, and limited reaction efficiency in traditional bioconjugation has restricted the booming development to some extent. Here, we provide a strategy for metal-free click bioconjugation at diverse levels based on activated alkynes. As a proof-of-concept, the abundant native groups including amine, thiol, and hydroxyl groups can directly react with activated alkynes without any modification in the absence of metal catalysis. Through this strategy, high-efficient modification and potential functionalization can be achieved for natural polysaccharide, biocompatible polyethylene glycol (PEG), synthetic polymers, cell penetrating peptide, protein, fast whole-cell mapping, and even quick differentiation and staining of Gram-positive bacteria, etc. Therefore, current metal-free click bioconjugation strategy based on activated alkynes is promising for the development of quick fluorescence labeling and functional modification of many targets and can be widely applied towards the fabrication of complex biomaterials and future in vivo labeling and detection.


2018 ◽  
Author(s):  
Sharada Duddu. S ◽  
Sagar Arepally ◽  
Arumugavel Murugan ◽  
Mamata Ojha

<p>An organic dye photoredox-catalyzed oxidative C-C triple bond cleavage <i>via</i> hydroamination leading to oxamates at room temperature has been described. The key features of this transformation are the mild conditions, metal-free organic dye as photocatalyst, broad amines scope, and a tandem hydroamination-oxidative C-C triple bond cleavage. </p>


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