Results 111 to 120 of about 44,314 (270)

Pyridine C─N Transposition via Cycloaddition–Cycloreversion

Angewandte Chemie, EarlyView.
Transposition of pyridine nitrogen from the 4‐ to the 3‐position is described using two open and shut sequences: a nucleophile addition ring‐open ring‐closure, followed by a nitrile Diels–Alder cycloaddition cycloreversion. The nitrogen swap is particularly effective for tertiary alkyl substituents, transforming easily accessible para‐alkylated ...
Aífe Conboy, Michael F. Greaney
wiley   +2 more sources

Mechanistic Insight Into the Polymorph‐Dependent Photosalient Effect of a White Light or Two‐Photon Activated Photoreactive Molecular Salt

Angewandte Chemie, EarlyView.
Photocycloaddition in stilbene‐type salt polymorphs exhibit distinct light‐driven responses: OHT‐TI shows a violent photosalient effect under visible and NIR (two‐photon) irradiation, whereas OHT‐TII reacts statically. Packing and computational analysis reveals that shell‐like structures in OHT‐TI frustrate structural relaxation, accumulating explosive
Emanuela Santagata, Francesco Ambrosio, Amedeo Capobianco, Andrea Peluso, Giorgia Rizzi, Stijn Van Cleuvenbergen, Yovan de Coene, Koen Clays, Paolo Pio Mazzeo, Roberto Centore, Fabio Borbone   +10 more
wiley   +2 more sources

From Mechanistic Study to Chiral Catalyst Optimization: Theoretical Insight into Binaphthophosphepine-catalyzed Asymmetric Intramolecular [3 + 2] Cycloaddition

Scientific Reports, 2017
Density functional M11 was used to study the mechanism and enantioselectivity of a binaphthophosphepine-catalyzed intramolecular [3 + 2] cycloaddition reaction.
Meng Duan, Lei Zhu, Xiaotian Qi, Zhaoyuan Yu, Yingzi Li, Ruopeng Bai, Yu Lan   +6 more
doaj   +1 more source

Síntese regiosseletiva de cristais líquidos contendo o heterociclo isoxazol [PDF]

, 2008
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Programa de Pós-Graduação em QuímicaMoléculas com características líquido-cristalinas têm ultimamente atraído um grande interesse por parte de ...
Bryk, Fernando Rebouças
core  

(4+3)-Cycloaddition of Donor-Acceptor Cyclopropanes with Thiochalcones: A Diastereoselective Access to Tetrahydrothiepines

, 2019
A general approach is described for the formation of tetrahydrothiepines using donor-acceptor cyclopropanes. Thiochalcones, functioning as sulfur-containing four-atom building blocks, were reacted in a Lewis-acid-catalyzed formal (4+3)-cycloaddition ...
André U., Augustin, J. Luca, Merz, Grzegorz, Mloston, Peter G., Jones, Daniel, Werz   +4 more
core   +1 more source

Catalytic Enantioselective Intramolecular Aza‐Michael Addition to α,β‐Unsaturated Esters

Angewandte Chemie, EarlyView.
A general method for accessing enantioenriched saturated N‐heterocycles via a catalytic enantioselective intramolecular aza‐Michael reaction to α,β‐unsaturated esters is described. A superbasic bifunctional iminophosphorane (BIMP) catalyst was key to enabling reactivity of the high pKa sulfonamide pronucleophile, whilst delivering good to excellent ...
Evan G. W. Rutter, Cameron J. MacRae, Haoran Xiong, Daniel Rozsar, Katherine F. P. Clarke, Darren J. Dixon   +5 more
wiley   +2 more sources

Spectroscopic Analysis of the Products of the Cycloaddition Reaction of 1-Aryl-2-chlorocyclopropenes and Cyclopentadiene

, 2014
[[abstract]]The treatment of a series of 1-aryl-2,2-dihalocyclopropanes with t-BuOK at −10 °C produces the corresponding 1-aryl-2-halocyclopropenes, which react with cyclopentadiene to produce fairly good yield of [4+2]-cycloaddition products with more ...
Din, Mei-Fang;Ding, Mei-Fang;李傳珍;Lee, Chuan-Chen;Li, Lian-Chun;Lin, Lian-Chun;Lin, Shaw-Tao;Lin, Shaw-Tao
core   +1 more source

Chemo- and Regioselective 1,3-Dipolar Cycloaddition of Nitrile Imines to 5-Arylmethylene-2-methylthiohydantoins

Organics
1,3-Dipolar cycloaddition reactions of nitrile imines are a powerful tool for the construction of spirocyclic frameworks, yet controlling chemoselectivity remains challenging when dipolarophiles contain multiple reactive sites.
Maria E. Filkina, Lev A. Lintsov, Victor A. Tafeenko, Maxim E. Kukushkin, Elena K. Beloglazkina   +4 more
doaj   +1 more source

Effect of the Nature of Surfactant on the Reactivity of C,N-diphenylnitrone towards Acrylonitrile in Different Microemulsions Systems

Chemistry Journal of Moldova: General, Industrial and Ecological Chemistry, 2018
The present work provides an insight into the effect of the nature of surfactant (cationic, anionic), a component of water- and oil-borne microemulsions, on the reaction rate of 1,3-dipolar cycloaddition of C,N-diphenylnitrone with acrylonitrile.
Kahina Hamza, Abdelkader Touati, Ahmed Ait-Yahia, Michel Baltas, Christiane André Barres, Saâd Moulay   +5 more
doaj   +1 more source

Recognition-Mediated Regiocontrol of a Dipolar Cycloaddition Reaction

, 2001
The rational design of a recognition-based system that is capable of accelerating and controlling the regiochemical outcome of a dipolar cycloaddition reaction between an azide and an alkyne is presented.
Spencer, Neil, Howell, SJ, Philp, Douglas   +2 more
core   +1 more source