Metal-free reductions of N-heterocycles via Lewis acid catalyzed hydrogenation

2010 ◽  
Vol 46 (27) ◽  
pp. 4884 ◽  
Author(s):  
Stephen J. Geier ◽  
Preston A. Chase ◽  
Douglas W. Stephan
Keyword(s):  
Lewis Acid ◽  
Metal Free ◽  
Acid Catalyzed

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.

A Metal‐Free, Organo Lewis Acid Catalyzed Synthesis of Highly Substituted Oxazoles

2019 ◽  
Vol 4 (31) ◽  
pp. 8973-8977 ◽  
Author(s):  
Gullapalli Kumaraswamy ◽  
Maram Gangadhar
Keyword(s):  
Lewis Acid ◽  
Metal Free ◽  
Acid Catalyzed

ChemInform Abstract: Metal-Free Reductions of N-Heterocycles via Lewis Acid Catalyzed Hydrogenation.

ChemInform ◽  
2010 ◽  
Vol 41 (47) ◽  
pp. no-no
Author(s):  
Stephen J. Geier ◽  
Preston A. Chase ◽  
Douglas W. Stephan
Keyword(s):  
Lewis Acid ◽  
Metal Free ◽  
Acid Catalyzed

scholarly journals Comparative DFT study of metal-free Lewis acid-catalyzed C–H and N–H silylation of (hetero)arenes: mechanistic studies and expansion of catalyst and substrate scope

RSC Advances ◽  
2019 ◽  
Vol 9 (64) ◽  
pp. 37675-37685
Author(s):  
Pan Du ◽  
Jiyang Zhao
Keyword(s):  
Lewis Acid ◽  
Dft Study ◽  
Mechanistic Studies ◽  
Metal Free ◽  
Acid Catalyzed

We investigated the mechanism of the dehydrosilylation of (hetero)arenes and extended the scope of the silylation catalysts and substrates.

Synthesis and Applications of Chiral Bicyclic Bisborane Catalysts

Synthesis ◽  
2021 ◽  
Author(s):  
Zhao-Ying Yang ◽  
Ming Zhang ◽  
Xiao-Chen Wang
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Asymmetric Hydrogenation ◽  
Acid Catalysts ◽  
Frustrated Lewis Pairs ◽  
Lewis Acid Catalysts ◽  
Lewis Bases ◽  
Metal Free ◽  
Hydrogenation Reactions ◽  
Acid Catalyzed

The development of chiral borane Lewis acid catalysts opened the door for transition-metal-free catalyzed asymmetric organic reactions. Herein, we have summarized our work on the preparation of two classes of novel chiral bicyclic bisborane Lewis acid catalysts derived from C2-symmetric [3.3.0] dienes and [4.4] dienes, respectively. These catalysts not only form frustrated Lewis pairs with Lewis bases to catalyze asymmetric hydrogenation reactions but also activate Lewis basic functional groups in traditional Lewis acid catalyzed asymmetric reactions.

Lewis acid-catalyzed 2-arylquinazoline formation from N′-arylbenzimidamides and paraformaldehyde

2016 ◽  
Vol 18 (21) ◽  
pp. 5773-5776 ◽  
Author(s):  
Xiufang Cheng ◽  
Huamin Wang ◽  
Fuhong Xiao ◽  
Guo-Jun Deng
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Efficient Procedure ◽  
Metal Free ◽  
Acid Catalyzed

An efficient procedure for the synthesis of 2-arylquinazolines from N′-arylbenzimidamides has been developed under transition-metal-free conditions.

Lewis acid-catalyzed regioselective C–H carboxamidation of indolizines with dioxazolones via an acyl nitrene type rearrangement

2021 ◽  
Author(s):  
Dan Song ◽  
Changfeng Huang ◽  
Peishi Liang ◽  
Baofu Zhu ◽  
Xiang Liu ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Metal Free ◽  
Acid Catalyzed

An efficient, direct, and novel Lewis acid-catalyzed regioselective C–H carboxamidation of indolizines with dioxazolones via an acyl nitrene type rearrangement under metal-free conditions has been documented.

Catalytic Carbonyl-Olefin Metathesis of Aliphatic Ketones: Iron(III) HomoDimers as Lewis Acidic Superelectrophiles

2018 ◽  
Author(s):  
Haley Albright ◽  
Paul S. Riehl ◽  
Christopher C. McAtee ◽  
Jolene P. Reid ◽  
Jacob R. Ludwig ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Olefin Metathesis ◽  
Acid Activation ◽  
Lewis Acid Catalysts ◽  
Distinct Mode ◽  
Aliphatic Ketones ◽  
Carbon Carbon Bond ◽  
Metathesis Reactions ◽  
Acid Catalyzed

<div>Catalytic carbonyl-olefin metathesis reactions have recently been developed as a powerful tool for carbon-carbon bond</div><div>formation. However, currently available synthetic protocols rely exclusively on aryl ketone substrates while the corresponding aliphatic analogs remain elusive. We herein report the development of Lewis acid-catalyzed carbonyl-olefin ring-closing metathesis reactions for aliphatic ketones. Mechanistic investigations are consistent with a distinct mode of activation relying on the in situ formation of a homobimetallic singly-bridged iron(III)-dimer as the active catalytic species. These “superelectrophiles” function as more powerful Lewis acid catalysts that form upon association of individual iron(III)-monomers. While this mode of Lewis acid activation has previously been postulated to exist, it has not yet been applied in a catalytic setting. The insights presented are expected to enable further advancement in Lewis acid catalysis by building upon the activation principle of “superelectrophiles” and broaden the current scope of catalytic carbonyl-olefin metathesis reactions.</div>

scholarly journals Comparison of Corn Stover Pretreatments with Lewis Acid Catalyzed Choline Chloride, Glycerol and Choline Chloride-Glycerol Deep Eutectic Solvent

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1170
Author(s):  
Yuan Zhu ◽  
Benkun Qi ◽  
Xinquan Liang ◽  
Jianquan Luo ◽  
Yinhua Wan
Keyword(s):  
Corn Stover ◽  
Lewis Acid ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Enzymatic Saccharification ◽  
Glycerol Solution ◽  
Cellulose Conversion ◽  
Biomass Processing ◽  
Acid Catalyzed ◽  
Highly Correlated

Herein, corn stover (CS) was pretreated by less corrosive lewis acid FeCl3 acidified solutions of neat and aqueous deep eutectic solvent (DES), aqueous ChCl and glycerol at 120 °C for 4 h with single FeCl3 pretreatment as control. It was unexpected that acidified solutions of both ChCl and glycerol were found to be more efficient at removing lignin and xylan, leading to higher enzymatic digestibility of pretreated CS than acidified DES. Comparatively, acidified ChCl solution exhibited better pretreatment performance than acidified glycerol solution. In addition, 20 wt% water in DES dramatically reduced the capability of DES for delignification and xylan removal and subsequent enzymatic cellulose saccharification of pretreated CS. Correlation analysis showed that enzymatic saccharification of pretreated CS was highly correlated to delignification and cellulose crystallinity, but lowly correlated to xylan removal. Recyclability experiments of different acidified pretreatment solutions showed progressive decrease in the pretreatment performance with increasing recycling runs. After four cycles, the smallest decrease in enzymatic cellulose conversion (22.07%) was observed from acidified neat DES pretreatment, while the largest decrease (43.80%) was from acidified ChCl pretreatment. Those findings would provide useful information for biomass processing with ChCl, glycerol and ChCl-glycerol DES.

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