Results 31 to 40 of about 44,314 (270)

Promotion mechanism of hydroxyl groups in catalyzing CO2 cycloaddition

Journal of CO2 Utilization
In this study, a series of hydroxy-functionalized quaternary ammonium salt catalysts, i.e., NEt3(HE)Br, NEt2(HE)2Br, NEt1(HE)3Br, and N(HE)4Br, were successfully prepared by quantitatively grafting hydrogen-bond donors (HBDs) as electrophilic sites on ...
Yiming Wang, Wensheng Wei, Yuxin Wang, Guangwen Xu, Jinggang Zhao, Lei Shi   +5 more
doaj   +1 more source

Unveiling the Chemistry of Higher-Order Cycloaddition Reactions within the Molecular Electron Density Theory

Chemistry, 2022
The higher-order cycloaddition (HOCA) reaction of tropone with cyclopentadiene (Cp) has been studied within the Molecular Electron Density Theory.
Luis R. Domingo, Mar Ríos-Gutiérrez, Patricia Pérez   +2 more
doaj   +1 more source

Unusual Structure-Energy Correlations in Intramolecular Diels–Alder Reaction Transition States

, 2014
Detailed analysis of calculated data from an experimental/computational study of intramolecular furan Diels–Alder reactions has led to the unusual discovery that the mean contraction of the newly forming C-C σ-bonds from the transition state to the ...
Robert L. Rae, Paterson, Martin; id_orcid, Żurek, Justyna, Justyna Żurek, Justyna M. Żurek, Rae, Robert, Robert Rae, Paterson, Martin J., Martin J. Paterson, Martin Paterson, Magnus Bebbington, Bebbington, Magnus, Żurek, Justyna M., Magnus W. P. Bebbington, Rae, Robert L.   +14 more
core   +1 more source

[2+2+2] Cycloaddition Reactions of Macrocyclic Systems Catalyzed by Transition Metals. A Review

Molecules, 2010
Polyalkyne and enediyne azamacrocycles are prepared from arenesulfonamides and various alkyne and alkene derivatives either under basic or neutral conditions.
Anna Roglans, Anna Pla-Quintana
doaj   +1 more source

Microwave-Assisted Regioselective Synthesis and 2D-NMR Studies of New 1,2,3-Triazole Compounds Derived from Acridone

Journal of Chemistry, 2021
A simple and mild protocol towards the synthesis of new 1,2,3-triazole compounds derived from acridone has been developed via regiospecific 1,3-dipolar cycloaddition reaction between 10-(prop-2-yn-1-yl)acridone derivatives and aromatic azides using CuI ...
Mohammed Aarjane, Siham Slassi, Bouchra Tazi, Amina Amine   +3 more
doaj   +1 more source

Synthetic studies on the bioactive tetramic acid JBIR-22 using a late stage Diels-Alder reaction

, 2015
The authors would like to thank the following for funding: Cancer Research UK (grants C21383/A6950 and C483/A10706)A late stage Diels-Alder reaction is used to prepare a mixture of JBIR-22, a natural product from the Equisetin family of tetramic acids ...
Healy, A. R., Westwood, Nicholas James
core   +1 more source

The Puzzle of the New Type of Intermediate in the Course of [2 + 2] Cycloaddition with the Participation of Conjugated Nitroalkenes: MEDT Computational Study

Molecules
The phenomena of regio- and stereoselectivity and the molecular mechanism of the [2 + 2] cycloaddition reaction between (E)-2-arylnitroethenes and the ynamine molecular system were analyzed using wb97xd/6-311 + G(d) (PCM) quantumchemical calculations. It
Radomir Jasiński, Agnieszka Kącka-Zych
doaj   +1 more source

[4 + 2]-Cycloadditions to 1 '-Phenyl-Substituted 3-Vinylindoles with N-Phenylmaleimide: An Access to New [a]Anellated Carbazole Derivatives

CHIMIA, 1987
The AlCl3-catalyzed [4 + 2]-cycloaddition of T-phenyl-substituted 3-vinylindoles with N-phenylmaleimide gives rise to new anellated carbazole derivatives with a high endo-preference.
Ludwig Pfeuffer, Ulf Pindur
doaj   +1 more source

Reactivity of (Z)-4-arylidene-5(4H)-oxazolones: [4+2] cycloaddition versus [4+3] cycloaddition/nucleophilic trapping [PDF]

, 2002
The use of different aluminum derivatives in the reaction between cyclopentadiene and (Z)-2-phenyl-4-arylidene-5(4H)-oxazolones, and in particular the use of different equivalents of the reagent, allows the modulation of the synthesis of the norbornane ...
Peregrina, J.M. [0000-0003-3778-7065], Avenoza, A. [0000-0002-5465-3555], Busto, J.H. [0000-0003-4403-4790], Cativiela, C.   +3 more
core   +1 more source

Design of Amine-Modified Zr–Mg Mixed Oxide Aerogel Nanoarchitectonics with Dual Lewis Acidic and Basic Sites for CO₂/Propylene Oxide Cycloaddition Reactions

Nanomaterials, 2022
The utilization of CO2 attracts much research attention because of global warming. The CO2/epoxide cycloaddition reaction is one technique of CO2 utilization. However, homogeneous catalysts with both Lewis acidic and basic and toxic solvents, such as DMF,
Yi-Feng Lin, Yu-Rou Lai, Hsiang-Ling Sung, Tsair-Wang Chung, Kun-Yi Andrew Lin   +4 more
doaj   +1 more source