Synthesis ofC2-Symmetric Bisamidines:  A New Type of Chiral Metal-Free Lewis Acid Analogue Interacting with Carbonyl Groups

2007 ◽  
Vol 72 (15) ◽  
pp. 5618-5624 ◽  
Author(s):  
Deniz Akalay ◽  
Gerd Dürner ◽  
Jan W. Bats ◽  
Michael Bolte ◽  
Michael W. Göbel
Keyword(s):  
Lewis Acid ◽  
Carbonyl Groups ◽  
Metal Free ◽  
Acid Analogue ◽  
New Type

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.

scholarly journals Polyphosphorhydrazone-Based Radical Dendrimers

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1230
Author(s):  
Vega Lloveras ◽  
José Vidal-Gancedo
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Contrast Agents ◽  
Biomedical Applications ◽  
Organic Radicals ◽  
Resonance Imaging ◽  
Metal Free ◽  
Antioxidant Agents ◽  
New Type ◽  
Paramagnetic Properties

The search for new biomedical applications of dendrimers has promoted the synthesis of new radical-based molecules. Specifically, obtaining radical dendrimers has opened the door to their use in various fields such as magnetic resonance imaging, as anti-tumor or antioxidant agents, or the possibility of developing new types of devices based on the paramagnetic properties of organic radicals. Herein, we present a mini review of radical dendrimers based on polyphosphorhydrazone, a new type of macromolecule with which, thanks to their versatility, new metal-free contrast agents are being obtained, among other possible applications.

Development of silica-supported frustrated Lewis pairs: highly active transition metal-free catalysts for the Z-selective reduction of alkynes

2016 ◽  
Vol 6 (3) ◽  
pp. 882-889 ◽  
Author(s):  
Kai C. Szeto ◽  
Wissam Sahyoun ◽  
Nicolas Merle ◽  
Jessica Llop Castelbou ◽  
Nicolas Popoff ◽  
...  
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Selective Reduction ◽  
Frustrated Lewis Pairs ◽  
Acid Base ◽  
Metal Free ◽  
Highly Active ◽  
Active Transition ◽  
Lewis Pairs

Supported Lewis acid/base systems based have been prepared and characterized.

Novel Naproxen Derivatives: Lewis Acid/Transition-metal Free Synthesis via C-C Bond Forming Reaction

2007 ◽  
Vol 4 (4) ◽  
pp. 292-295 ◽  
Author(s):  
Sarbani Pal ◽  
P. Bindu ◽  
Pragnyadhar Reddy Venna ◽  
P. K. Dubey
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Metal Free ◽  
Bond Forming

An Unprecedented, Lewis Acid-Mediated, Metal-Free Iodoannulation Strategy to Aromatic Iodides

2018 ◽  
Vol 13 (23) ◽  
pp. 3676-3680
Author(s):  
Trisha Banik ◽  
Vipul V. Betkekar ◽  
Krishna P. Kaliappan
Keyword(s):  
Lewis Acid ◽  
Metal Free

scholarly journals Enantioselective Diels–Alder reaction of anthracene by chiral tritylium catalysis

2019 ◽  
Vol 15 ◽  
pp. 1304-1312 ◽  
Author(s):  
Qichao Zhang ◽  
Jian Lv ◽  
Sanzhong Luo
Keyword(s):  
Lewis Acid ◽  
Acid Catalyst ◽  
Alder Reaction ◽  
Ion Pair ◽  
Diels Alder ◽  
Highly Active ◽  
Diels Alder Reaction ◽  
New Type ◽  
Lewis Acid Catalyst ◽  
Trityl Cation

The combination of the trityl cation and a chiral weakly coordinating Fe(III)-based bisphosphate anion was used to develop a new type of a highly active carbocation Lewis acid catalyst. The stereocontrol potential of the chiral tritylium ion pair was demonstrated by its application in an enantioselective Diels–Alder reaction of anthracene.

Lewis-Acid-Assisted “Tandem Claisen Rearrangement”: Application to the Synthesis of a New Type of Macrocycle Containing Phenolic Moieties

1998 ◽  
Vol 27 (4) ◽  
pp. 307-308 ◽  
Author(s):  
Hirotaka Uzawa ◽  
Kazuhisa Hiratani ◽  
Norihiko Minoura ◽  
Toshikazu Takahashi
Keyword(s):  
Lewis Acid ◽  
Claisen Rearrangement ◽  
New Type
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