Results 21 to 30 of about 27,886 (261)

[3+2] Cycloaddition of alkyl aldehydes and alkynes enabled by photoinduced hydrogen atom transfer

open access: yesNature Communications, 2022
In contrast to the prevalence of 1,3-dipolar cycloadditions, radical [3+2] annulations of alkynes are underexplored. Here, the authors describe [3+2] cycloadditions of various internal alkynes with readily accessible aliphatic aldehydes via photoinduced ...
Siya Le   +6 more
doaj   +1 more source

The Azide-Allene Dipolar Cycloaddition: Is DFT Able to Predict Site- and Regio-Selectivity?

open access: yesMolecules, 2021
The site- and regio-selectivity of thermal, uncatalysed 1,3-dipolar cycloadditions between arylazides and mono- or tetra-substituted allenes with different electronic features have been investigated by both conceptual (reactivity indices) and ...
Giorgio Molteni, Alessandro Ponti
doaj   +1 more source

Nanoparticle‐Catalysed 1,3‐Dipolar Cycloadditions

open access: yesEuropean Journal of Organic Chemistry, 2020
The 1,3‐dipolar cycloadditions of azomethine‐ylides and ‐imines, nitrones, nitrilimines, and azides catalysed by inorganic nanoparticles are described. Emphasis is given to the nanometric catalysts involved, their structure, characterisation, and recyclability and, when remarkable, their preparation.
Ponti A., Molteni G.
openaire   +4 more sources

1,3-Dipolar cycloadditions of 2-thio-3-chloroacrylamides with nitrile oxides and nitrones [PDF]

open access: yes, 2010
1,3-Dipolar cycloadditions of 2-thio-3-chloroacrylamides with nitrile oxides and nitrones is described. A series of novel isoxazolines are isolated from the nitrile oxide cycloadditions, whilst the isoxazolines generated from the nitrone cycloadditions ...
Kissane, Marie   +2 more
core   +1 more source

Cycloadditions with 2-Chloro-1-Nitroethylene

open access: yesCHIMIA, 1975
2-chloronitroethylene replaces successfully the still elusive unsubstituted nitroacetylene in both the 1,3-dipolar and Diels-Alder cycloadditions. These reactions generally afford interesting nitrated cyclic and heterocyclic compounds.
R. Verbruggen, H.G. Viehe
doaj   +1 more source

Discovery of new mutually orthogonal bioorthogonal cycloaddition pairs through computational screening. [PDF]

open access: yes, 2015
Density functional theory (DFT) calculations and experiments in tandem led to discoveries of new reactivities and selectivities involving bioorthogonal sydnone cycloadditions.
Houk, KN   +3 more
core   +1 more source

Crystal and Molecular Structures of N-benzyl-C-(2-pyridyl) nitrone and its ZnBr2 Complex. A Study of Their Reactivity

open access: yesMolecules, 2001
The ZnBr2 complex of the title compound has been studied by both structural and theoretical methods. Similar reactivities have been observed for the nitrone alone and the complex in 1,3-dipolar cycloadditions and nucleophilic additions.
Tomas Tejero   +5 more
doaj   +1 more source

1,3-Dipolar cycloadditions of 2-thio-3-chloroacrylamides with diazoalkanes [PDF]

open access: yes, 2010
2-Thio-3-chloroacrylamides undergo 1,3-dipolar cycloadditions with diazoalkanes leading to a series of novel pyrazolines and pyrazoles. The mechanistic and synthetic features of the cycloadditions to the 2-thio-3-chloroacrylamides at both the sulfide and
Kissane, Marie   +2 more
core   +1 more source

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