Results 21 to 30 of about 16,682 (222)

Nitrile Oxide, Alkenes, Dipolar Cycloaddition, Isomerization and Metathesis Involved in the Syntheses of 2-Isoxazolines

open access: yesMolecules, 2023
The involvement of 1,3-dipolar cycloaddition (1,3-DP), double bond migration, metathesis, and nitrile oxide (including in situ-generated nitrile oxide) as dipoles, together with the C=C bond containing dipolarophiles, in the syntheses of 2-isoxazolines ...
Stanisław Krompiec   +7 more
doaj   +1 more source

Organocatalyzed Enantio- and Diastereoselective Domino [3+2]-Dipolar Cycloaddition: Synthesis of Chiral Pyrrorlo-thiazine-2-carbaldehydes and Dihydropyrrole-3-carbaldehydes [PDF]

open access: yes, 2023
1,3-Dipolar cycloaddition of azomethine ylide and dipolarophile is an efficient method to construct N, S heterocycles such as thiazoles, 1,4-thiazines, and their chiral polyhydro derivatives.
Venkata Surya Kumar , Choutipalli   +3 more
core   +1 more source

1,3 dipolar cycloaddition of münchnones: Factors behind the regio-selectivity [PDF]

open access: yes, 2022
The 1,3 dipolar cycloaddition reactions of münchnones and alkenes provide an expedite synthetic way to substituted pyrroles, an exceedingly important structural motif in the pharmaceutical and material science fields of research.
Juan J., González Armesto   +3 more
core   +1 more source

On the strong difference in reactivity of acyclic and cyclic diazodiketones with thioketones: experimental results and quantum-chemical interpretation

open access: yesBeilstein Journal of Organic Chemistry, 2015
The 1,3-dipolar cycloaddition of acyclic 2-diazo-1,3-dicarbonyl compounds (DDC) and thioketones preferably occurs with Z,E-conformers and leads to the formation of transient thiocarbonyl ylides in two stages.
Andrey S. Mereshchenko   +5 more
doaj   +1 more source

Nitropyridines as 2π-Partners in 1,3-Dipolar Cycloadditions with N-Methyl Azomethine Ylide: An Easy Access to Condensed Pyrrolines

open access: yesMolecules, 2021
1,3-Dipolar cycloaddition reactions of 2-substituted 5-R-3-nitropyridines and isomeric 3-R-5-nitropyridines with N-methyl azomethine ylide were studied. The effect of the substituent at positions 2 and 5 of the pyridine ring on the possibility of the [3 ...
Maxim A. Bastrakov   +3 more
doaj   +1 more source

A Stepwise [4 + 3] Cycloaddition Reaction of the 1,3-Diphenyl-2-azaallyl Anion [PDF]

open access: yes, 1993
The 1,3-diphenyl-2-azaallyl anion (1) undergoes [3 + 2] cycloaddition reactions with the s-cis-fixed 1,3-dienes 8-11. In contrast, 1,1,2,2,3,3-hexamethyl-4,5-bis(methylene)cyclopentane (7) reacts with 1 to give the [4 + 3] cycloadduct 13 and the linear 1,
Mayr, Herbert   +2 more
core   +1 more source

Kinetic Resolution of Alkylidene Norcamphors via a Ligand-Controlled Umpolung-Type 1,3-Dipolar Cycloaddition

open access: yesiScience, 2019
Summary: Development of a general catalytic and highly efficient method utilizing readily available precursors for the regio- and stereoselective construction of bioactive natural-product-inspired spiro architectures remains a formidable challenge in ...
Chong Shen   +5 more
doaj   +1 more source

Intramolecular Azide to Alkene Cycloadditions for the Construction of Pyrrolobenzodiazepines and Azetidino-Benzodiazepines [PDF]

open access: yes, 2014
The coupling of proline- and azetidinone-substituted alkenes to 2-azidobenzoic and 2-azidobenzenesulfonic acid gives precursors that undergo intramolecular azide to alkene 1,3-dipolar cycloadditions to give imine-, triazoline- or aziridine-containing ...
O'Gorman, Paul A   +11 more
core   +1 more source

Photo‐Triggered, Fast, and Fluorogenic Thiophene‐Based Cycloalkynes for the Bioorthogonal Fluorescent Labeling of 1,3‐Dipole‐Tagged Molecules in No‐Wash Conditions

open access: yesAngewandte Chemie, EarlyView.
Thiophene is king! The fusion of thiophene rings to cycloalkynes super‐charged their copper‐free click chemistry applications, by (1) enhancing the alkyne reactivity (fastest cyclooctyne to date) and (2) rendering the alkyne fluorogenic (with fluorescence enhancement up to 150‐fold upon reaction), making these bioorthogonal reagents ideal for tracking ...
Jurgen Schulz   +7 more
wiley   +2 more sources

N-Alkylated dinitrones from isosorbide as cross-linkers for unsaturated bio-based polyesters

open access: yesBeilstein Journal of Organic Chemistry, 2014
Isosorbide was esterified with acryloyl chloride and crotonic acid yielding isosorbide diacrylate (9a) and isosorbide dicrotonate (9b), which were reacted with benzaldehyde oxime in the presence of zinc(II) iodide and boron triflouride etherate as ...
Oliver Goerz, Helmut Ritter
doaj   +1 more source

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