A metal-free yne-addition/1,4-aryl migration/decarboxylation cascade reaction of alkynoates with Csp3–H centers

2016 ◽  
Vol 14 (7) ◽  
pp. 2210-2217 ◽  
Author(s):  
De-Long Kong ◽  
Liang Cheng ◽  
Hong-Ru Wu ◽  
Yang-Xiong Li ◽  
Dong Wang ◽  
...  
Keyword(s):  
Cascade Reaction ◽  
Single Site ◽  
Metal Free ◽  
Different Types

Reactions of alkynoates with different types of radical precursors under metal-free conditions affording single-site-addition poly-substituted alkenes were reported.

A metal-free radical cascade reaction of phosphine oxides with 2-aryloxy phenylacetylenes to assemble diphosphonyl xanthene derivatives

2021 ◽  
Author(s):  
Tao Fan ◽  
Yan Liu ◽  
Caina Jiang ◽  
Yanli Xu ◽  
Yan-Yan Chen
Keyword(s):  
Free Radical ◽  
Transition Metal ◽  
Cascade Reaction ◽  
Phosphine Oxides ◽  
Metal Free ◽  
Mild Conditions ◽  
Xanthene Derivatives ◽  
Reaction Proceeds ◽  
Radical Cascade

A radical cascade reaction of 2-aryloxy phenylacetylene with phosphine oxides promoted by K2S2O8 was developed, provided diphosphonyl xanthenes as products. This reaction proceeds under transition metal-free and mild conditions with...

Effect of Surface Chemistry on Ruthenium Wet Etching

2021 ◽  
Vol 314 ◽  
pp. 302-306
Author(s):  
Quoc Toan Le ◽  
E. Kesters ◽  
M. Doms ◽  
Efrain Altamirano Sánchez
Keyword(s):  
Surface Roughness ◽  
Photoelectron Spectroscopy ◽  
Etching Rate ◽  
Wet Etching ◽  
X Ray ◽  
Force Microscopy ◽  
Metal Free ◽  
Atomic Force ◽  
Different Types ◽  
Effect Of Surface

Different types of ALD Ru films, including as-deposited, annealed Ru, without and with a subsequent CMP step, were used for wet etching study. With respect to the as-deposited Ru, the etching rate of the annealed Ru film in metal-free chemical mixtures (pH = 7-9) was found to decrease substantially. X-ray photoelectron spectroscopy characterization indicated that this behavior could be explained by the presence of the formation of RuOx (x = 2,3) caused by the anneal. A short CMP step applied to the annealed Ru wafer removed the surface RuOx, at least partially, resulting in a significant increase of the etching rate. The change in surface roughness was quantified using atomic force microscopy.

scholarly journals ESTRATÉGIAS DE CIMENTAÇÃO EM RESTAURAÇÕES LIVRES DE METAL: UMA ABORDAGEM SOBRE TRATAMENTOS DE SUPERFÍCIE E CIMENTOS RESINOSOS

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Andréa Maria Silva ◽  
Viviane Figueiredo ◽  
Alcione Farias ◽  
Nadja Maria Brito ◽  
Maria Helena Catão ◽  
...  
Keyword(s):  
Decision Making ◽  
Surface Treatment ◽  
Clinical Success ◽  
Ceramic System ◽  
Metal Free ◽  
Restorative Treatment ◽  
Different Types ◽  
Success Of Treatment ◽  
Proper Strategy ◽  
Cementing Agent

The metal-free restorations are sought out due to aesthetic needs. The success of restorative treatment depends on the peculiarities of each ceramic system and on a proper strategy for cementing. This article presents the surface treatment of the interfaces involved during the cementing, the dental structure and restoration, and elucidates the cementing agent. It emphasizes the different types of surface treatment for acid-sensitive and acid-resistant ceramics, and hybrid ceramics. The literature review was based on scientific articles published in different database (PubMed, Medline, Scielo, Bireme and Google Scholar) using the keywords: prosthodontics, ceramics, surface treatment and cementation. Relevant articles were selected between 2002 and 2015 regarding the issue under review. The knowledge of dentists about the cementation strategies, depending on the type of ceramic used, is necessary for decision making during the cementing and promote the clinical success of treatment with metal-free restorations.

A transition-metal-free multicomponent reaction towards constructing chiral 2H-1,4-benzoxazine scaffolds

2020 ◽  
Vol 22 (21) ◽  
pp. 7506-7512
Author(s):  
Lixiang Zhu ◽  
Xiaoyu Ren ◽  
Juan Du ◽  
Jia-Hong Wu ◽  
Jian-Ping Tan ◽  
...  
Keyword(s):  
Transition Metal ◽  
Multicomponent Reaction ◽  
Phosphonium Salt ◽  
Cascade Reaction ◽  
Metal Free

A transition-metal-free multicomponent cascade reaction of α-halogenated ketones, ortho-aminophenols, and aldehydes using a dipeptide phosphonium salt catalyst was developed for the construction of various 2H-1,4-benzoxazines.

De novo synthesis of benzofurans via trifluoroacetic acid catalyzed cyclization/oxidative aromatization cascade reaction of 2-hydroxy-1,4-diones

2019 ◽  
Vol 17 (32) ◽  
pp. 7547-7551 ◽  
Author(s):  
Qiang Sha ◽  
Haixuan Liu
Keyword(s):  
Trifluoroacetic Acid ◽  
De Novo ◽  
Cascade Reaction ◽  
De Novo Synthesis ◽  
Simple Metal ◽  
Metal Free ◽  
Aromatization Reaction ◽  
Oxidative Aromatization ◽  
Acid Catalyzed

A simple metal-free cyclization/oxidative aromatization reaction starting from 2-hydroxy-1,4-diones for the de novo synthesis of benzofurans was developed.

Stereoselective three-component cascade synthesis of α-substituted 2,4-dienamides from gem-difluorochloro ethanes

2019 ◽  
Vol 55 (95) ◽  
pp. 14355-14358
Author(s):  
Shyamsundar Das ◽  
Nakeun Ko ◽  
Eunsung Lee ◽  
Sang Eun Kim ◽  
Byung Chul Lee
Keyword(s):  
Transition Metal ◽  
Claisen Rearrangement ◽  
Cascade Reaction ◽  
One Pot ◽  
Metal Free

Herein, we describe a new transition metal-free Claisen rearrangement for the synthesis of α-substituted 2,4-dienamide. This one-pot, stereoselective three-component cascade reaction affords various polysubstituted 2,4-dienamides in good yields.

Multicomponent Cascade Reaction by Metal-Free Aerobic Oxidation for Synthesis of Highly Functionalized 2-Amino-4-coumarinyl-5-arylpyrroles

2019 ◽  
Vol 85 (2) ◽  
pp. 327-338 ◽  
Author(s):  
Quan-Xing Zi ◽  
Chang-Long Yang ◽  
Kun Li ◽  
Qin Luo ◽  
Jun Lin ◽  
...  
Keyword(s):  
Aerobic Oxidation ◽  
Cascade Reaction ◽  
Metal Free

One-pot transition-metal-free cascade synthesis of thieno[2,3-c]coumarins from chromones

RSC Advances ◽  
2016 ◽  
Vol 6 (106) ◽  
pp. 103895-103898 ◽  
Author(s):  
Yuhong Yang ◽  
Xueyu Qi ◽  
Ruiling Liu ◽  
Qian He ◽  
Chunhao Yang
Keyword(s):  
Transition Metal ◽  
Cascade Reaction ◽  
Free Base ◽  
One Pot ◽  
Metal Free

A one-pot transition-metal-free, base-mediated synthesis of a novel series of functionalized thieno[2,3-c]coumarins has been developed through a cascade reaction from chromones.

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