Metal-free synthesis of triarylated (Z)-nitrones via H2O-mediated 1,3-dipolar transfer under aerobic conditions

2019 ◽  
Vol 21 (3) ◽  
pp. 675-683 ◽  
Author(s):  
Ke Chen ◽  
Wen-Juan Hao ◽  
Shu-Jiang Tu ◽  
Bo Jiang
Keyword(s):  
Good Yield ◽  
Transfer Reaction ◽  
Environmentally Benign ◽  
Quinone Methides ◽  
Aerobic Conditions ◽  
Metal Free ◽  
Catalyst Free

A new and environmentally benign protocol aimed at the generation of triarylated (Z)-nitrones in generally good yield has been developed via metal- and catalyst-free H2O-mediated 1,3-dipolar transfer reaction of para-quinone methides (p-QMs) with diarylated nitrones under aerobic conditions.

Saccharin and tert-Butyl Nitrite: Cheap and Efficient Reagents for the Synthesis of 1,2,3-Benzotriazine-4-(3H)-ones from 2-Aminobenzamides under Metal-Free Conditions

2018 ◽  
Vol 71 (3) ◽  
pp. 186 ◽  
Author(s):  
Nader Ghaffari Khaligh ◽  
Mohad Rafie Johan ◽  
Juan Joon Ching
Keyword(s):  
Energy Efficiency ◽  
Cost Effectiveness ◽  
Good Yield ◽  
Current Method ◽  
Environmentally Benign ◽  
Efficient Catalyst ◽  
Experimental Procedure ◽  
Metal Free ◽  
Tert Butyl ◽  
First Time

A mild and eco-friendly protocol for the synthesis of 1,2,3-benzotriazine-4-(3H)-ones is described using saccharin as a cheap and efficient catalyst and tert-butyl nitrite as a diazotization reagent for the first time. The current method has advantages such as cost effectiveness, energy efficiency, and simple experimental procedure, good yield of the desired product, and metal-free and environmentally benign conditions.

Catalyst-free 1,6-conjugate addition of indoles and 4-hydroxycoumarins to para-quinone methides: synthesis of unsymmetrical triarylmethanes

2020 ◽  
Vol 18 (39) ◽  
pp. 7837-7841
Author(s):  
Subramani Kumaran ◽  
Mohan Prabhakaran ◽  
Narayanan Mariyammal ◽  
Kanniyappan Parthasarathy
Keyword(s):  
Michael Reaction ◽  
Conjugate Addition ◽  
Quinone Methides ◽  
Metal Free ◽  
Catalyst Free

We have successfully developed an efficient metal-free 1,6-Michael reaction of indoles and 4-hydroxycoumarins with para-quinone methides to afford heterocyclic triarylmethanes in good yields.

Metal-Free Photoinduced Hydroalkylation Cascade Enabled by an Electron-Donor-Acceptor Complex

2020 ◽  
Author(s):  
José Tiago Menezes Correia ◽  
Gustavo Piva da Silva ◽  
Camila Menezes Kisukuri ◽  
Elias André ◽  
Bruno Pires ◽  
...  
Keyword(s):  
Electron Donor ◽  
Functional Group ◽  
Photoexcited Electron ◽  
One Pot ◽  
Quaternary Centers ◽  
Metal Free ◽  
Acceptor Complex ◽  
Catalyst Free ◽  
Donor Acceptor ◽  
Radical Cascade

A metal- and catalyst-free photoinduced radical cascade hydroalkylation of 1,7-enynes has been disclosed. The process is triggered by a SET event involving a photoexcited electron-donor-aceptor complex between NHPI ester and Hantzsch ester, which decomposes to afford a tertiary radical that is readily trapped by the enyne. <a>The method provides an operationally simple, robust and step-economical approach to the construction of diversely functionalized dihydroquinolinones bearing quaternary-centers. A sequential one-pot hydroalkylation-isomerization approach is also allowed giving access to a family of quinolinones. A wide substrate scope and high functional group tolerance was observed in both approaches</a>.

Catalyst-free synthesis of phenanthridines via electrochemical coupling of 2-isocyanobiphenyls and amines

2021 ◽  
Vol 45 (14) ◽  
pp. 6367-6378
Author(s):  
Bhanwar Kumar Malviya ◽  
Karandeep Singh ◽  
Pradeep K. Jaiswal ◽  
Manvika Karnatak ◽  
Ved Prakash Verma ◽  
...  
Keyword(s):  
One Pot ◽  
Metal Free ◽  
Catalyst Free ◽  
Electrochemical Coupling

One pot metal-free synthesis of phenanthridines and amides under electrochemical conditions.

scholarly journals Metal-Free Catalysts for the Polymerization of Alkynyl-Based Monomers

Catalysts ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 1 ◽  
Author(s):  
Jie Zhang ◽  
Zhiming Zhang ◽  
Fulin Yang ◽  
Haoke Zhang ◽  
Jingzhi Sun ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Research Focus ◽  
Catalytic Systems ◽  
Metal Free ◽  
Catalyst Free ◽  
Material Sciences ◽  
Acid Catalyzed

Novel polymerizations based on alkyne monomers are becoming a powerful tool to construct polymers with unique structures and advanced functions in the areas of polymer and material sciences, and scientists have been attracted to develop a variety of novel polymerizations in recent decades. Therein, catalytic systems play an indispensable role in the influence of polymerization efficiencies and the performances of the resultant polymers. Concerning the shortcomings of metallic catalysts, much of the recent research focus has been on metal-free polymerization systems. In this paper, metal-free catalysts are classified and the corresponding polymerizations are reviewed, including organobase-catalyzed polymerizations, Lewis-acid-catalyzed polymerizations, as well as catalyst-free polymerizations. Moreover, the challenges and perspectives in this area are also briefly discussed.

Electrochemical Oxidative Cyclization of Alkenes, Boronic Acids, and Dichalcogenides to Access Chalcogenated Boronic Esters and 1,3-Diols

2021 ◽  
Author(s):  
Changfeng Huang ◽  
Jijing Hu ◽  
Guangxian Chen ◽  
Minjian Wu ◽  
Hua Cao ◽  
...  
Keyword(s):  
Boronic Acids ◽  
Oxidative Cyclization ◽  
Environmentally Benign ◽  
Allylic Alcohols ◽  
Efficient Manner ◽  
Metal Free ◽  
Boronic Esters

A sustainable, environmentally benign electrochemical oxidative three-component cyclization of allylic alcohols, boronic acids, and dichalcogenides under metal-free and oxidant-free conditions has been developed, which provides an efficient manner for the...

Efficient Synthesis of Chromenes from Vinyl o-Quinone Methides via a Brønsted Acid Catalyzed Electrocyclization Process

Synthesis ◽  
2018 ◽  
Vol 50 (12) ◽  
pp. 2416-2422 ◽  
Author(s):  
Man-Su Tu ◽  
Guang-Jian Mei ◽  
Feng Shi ◽  
Si-Jia Liu ◽  
Xiao-Li Jiang ◽  
...  
Keyword(s):  
Efficient Method ◽  
Research Area ◽  
Environmentally Benign ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Efficient Synthesis ◽  
Quinone Methides ◽  
Efficient Approach ◽  
Brönsted Acid ◽  
Acid Catalyzed

An efficient approach for the synthesis of chromene derivatives from vinyl o-quinone methides was established via a Brønsted acid catalyzed electrocyclization. By using this methodology, a series of structurally diversified chromenes was synthesized in a highly atom-economic and environmentally benign manner with generally good to excellent yields (up to 98% yield). This reaction will not only provide an efficient method for the construction of chromene scaffolds, but also enrich the research area of o-quinone methides.

One-pot transition-metal free transamidation to sterically hindered amides

2018 ◽  
Vol 5 (20) ◽  
pp. 2950-2954 ◽  
Author(s):  
Weijie Guo ◽  
Jingjun Huang ◽  
Hongxiang Wu ◽  
Tingting Liu ◽  
Zhongfeng Luo ◽  
...  
Keyword(s):  
Transition Metal ◽  
Good Yield ◽  
One Pot ◽  
Metal Free ◽  
Highly Efficient ◽  
Sterically Hindered

A highly efficient one-pot transamidation of primary amides has been developed under transition-metal free conditions, generating a variety of amides including hindered amides in good yield (up to 86%) catalyzed by CsF.

Direct C–H sulfenylation of quinoxalinones with thiols under visible-light-induced photocatalyst-free conditions

2019 ◽  
Vol 21 (23) ◽  
pp. 6241-6245 ◽  
Author(s):  
Qing-Hu Teng ◽  
Yan Yao ◽  
Wen-Xiu Wei ◽  
Hai-Tao Tang ◽  
Jia-Rong Li ◽  
...  
Keyword(s):  
Visible Light ◽  
Metal Free ◽  
Catalyst Free

We have developed a metal-free and catalyst-free visible-light-promoted direct C–H sulfenylation of quinoxalin-2(1H)-ones with thiols for the synthesis of diverse 3-sulfenylquinoxalin-2(1H)-ones.

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