Results 91 to 100 of about 42,977 (261)

Microwave-Assisted Synthesis of Fluorescent Pyrido[2,3-b]indolizines from Alkylpyridinium Salts and Enaminones

Molecules, 2020
Pyridinium ylides are well recognized as dipoles for cycloaddition reactions. In its turn, the microwave-assisted interaction of N-(cyanomethyl)-2-alkylpyridinium salts with enaminones unexpectedly proceeds as a domino sequence of cycloisomerization and ...
Ekaterina A. Sokolova, Alexey A. Festa, Karthikeyan Subramani, Victor B. Rybakov, Alexey V. Varlamov, Leonid G. Voskressensky, Erik V. Van der Eycken   +6 more
doaj   +1 more source

Nitrones as Versatile Linkages for the Construction of Covalent Organic Polymers by Tandem Transformations

ChemistryEurope, EarlyView.
The nitrone moiety's versatility in covalent organic polymer (COP) materials is shown by its ability to form either nitrone‐linked or oxime O‐ether‐linked COPs from the same building blocks, simply by changing reaction conditions. Additionally, its 1,3‐dipolar cycloaddition reactivity enabled the synthesis of a functionalized isoxazolidine‐linked ...
Beatriz de Santos, M. José Capitán, Jesús Álvarez, Isabel Sobrados, Silvia Cabrera, Alberto Fraile, José Alemán   +6 more
wiley   +1 more source

Intermolecular 1,3-dipolar cycloadditions of azomethine imines [PDF]

Arkivoc, 2006
Dipolar cycloadditions of azomethine imines, formed in situ from aldehydes and N1-alkyl-N2-acylhydrazines, with electron-deficient dipolarophiles produce pyrazolidines: mono-substituted dipolarophiles afford principally 4-substituted pyrazolidines.
Jones, Raymond C.F., Hollis, Stephen J., Iley, James N.   +2 more
openaire   +4 more sources

Glycerol: a biorenewable solvent for base-free Cu(I)-catalyzed 1,3-dipolar cycloaddition of azides with terminal and 1-iodoalkynes. Highly efficient transformations and catalyst recycling [PDF]

, 2014
Ministerio de Ciencia e Innovacin (MICINN) of Spain [CTQ2010-14796, RYC-2011-08451]; MICINN; European Social ...
García Álvarez, Joaquín, Vidal Vides, Christian   +1 more
core   +1 more source

Decarboxylation-Driven Double Annulations: Innovative Multi-Component Reaction Pathways

Molecules
A concerted five-component reaction strategy has been developed, featuring double [3+2] cycloadditions utilizing aspartic acid. This approach provides valuable insights into mechanistic pathways, allowing for the distinction between concerted and ...
Desheng Zhan, Gang Yang, Tieli Zhou, Sashirekha Nallapati, Xiaofeng Zhang   +4 more
doaj   +1 more source

Imidazoline‐Proline and Imidazoline‐Prolinate Ligands for Copper‐Catalyzed Asymmetric Exo‐Selective [3 + 2] Cycloaddition of Iminoesters with Nitroalkenes

ChemistryEurope, EarlyView.
From a modular synthesis of nonphosphine chiral nitrogen‐based chiral imidazoline–amino acid ligands, two new chiral imidazoline–proline‐copper catalysts are developed for targeting exo‐selective [3 + 2] cycloaddition reaction. Density functional theory studies rationalize the observed stereoselectivity and the distinct chiral pockets of the two ...
Yan Yu, Takuya Shimada, Chihiro Tokumitsu, Ayaka Fujiwara, Takayoshi Arai   +4 more
wiley   +1 more source

Concerted [4 + 2] and Stepwise (2 + 2) Cycloadditions of Tetrafluoroethylene with Butadiene: DFT and DLPNO-UCCSD(T) Explorations. [PDF]

, 2020
Tetrafluoroethylene and butadiene form the 2 + 2 cycloadduct under kinetic control, but the Diels-Alder cycloadduct is formed under thermodynamic control. Borden and Getty showed that the preference for 2 + 2 cycloaddition is due to the necessity for syn-
Houk, KN, Liu, Peng, Mackey, Joel L, Pemberton, Ryan P, Svatunek, Dennis   +4 more
core  

Synthesis of 3,5-Disubstituted Isoxazoles and Isoxazolines in Deep Eutectic Solvents [PDF]

, 2015
The synthesis of different 3,5-disubstituted isoxazoles and related isoxazolines using choline chloride:urea as deep eutectic solvent (DES) in a one-pot three step reaction has been accomplished successfully. The use of highly nucleophilic functionalized
Pérez Galera, Juana María, Ramón, Diego J.   +1 more
core   +3 more sources

Pd(II)‐Catalyzed Strategies for the β‐Arylation of α‐Amino Acids: An Overview

Chemistry – A European Journal, EarlyView.
The graphical abstract summarizes the review “Pd(II)‐Catalyzed Strategies for the β‐Arylation of α‐Amino Acids: An Overview”, highlighting representative Pd(II)‐catalyzed methods for the β‐arylation of α‐amino acids. Key mechanistic features, substrate diversity, and synthetic relevance of these transformations are showcased. Abstract Metal‐catalyzed C─
Davide Illuminati, Claudio Trapella, Vinicio Zanirato, Virginia Cristofori, Anna Fantinati   +4 more
wiley   +1 more source

Asymmetric Lewis acid-catalyzed 1,3-dipolar cycloadditions [PDF]

, 2017
Highly tuned, one-point binding chiral iron and ruthenium complexes selectively coordinate and activate α,β-unsaturated aldehydes and ketones toward asymmetric catalytic Diels-Alder cycloaddition reactions.
Brinkmann, Yasmin, Bădoiu, Andrei, Kündig, E. Peter, Viton, Florian   +3 more
core