Results 11 to 20 of about 8,699 (217)

Decarboxylation-Driven Double Annulations: Innovative Multi-Component Reaction Pathways [PDF]

open access: yesMolecules
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   +4 more
doaj   +2 more sources

1,3-Dipolar cycloadditions of azomethine imines [PDF]

open access: yesOrganic & Biomolecular Chemistry, 2015
Azomethine imines react with alkenes and alkynes to give pyrazolines, pyrazolidines, pyrazolopyridines, indazoloisoquinolines, pyrazolo[1,5-a]isoquinolines and pyrazolopyrazolones through regio-, stereo- and enantioselective 1,3-dipolar cycloadditions.
Nájera, Carmen   +2 more
openaire   +6 more sources

Transition-state aromaticity and its relationship with reactivity in pericyclic reactions [PDF]

open access: yesBeilstein Journal of Organic Chemistry
The influence of transition-state aromaticity on the barrier heights of concerted pericyclic reactions is summarized herein. To this end, selected representative examples ranging from fundamental processes such as Diels–Alder or Alder–ene reactions to ...
Israel Fernández
doaj   +2 more sources

[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

Studies on the [2+3] cycloaddition reaction of nitrile oxides to abietic acid esters [PDF]

open access: yesJournal of the Serbian Chemical Society, 2019
[2+3] Dipolar cycloadditions of aromatic nitrile oxides to abietic acid esters were investigated. The reactions showed complete site selectivity and regioselectivity, while the stereoselectivity depended on the structures of the dipolarophiles.
Gucma Mirosław   +3 more
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

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

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

Orthogonal, metal-free surface modification by strain-promoted azide–alkyne and nitrile oxide–alkene/alkyne cycloadditions [PDF]

open access: yes, 2012
In this article we present a fast and efficient methodology for biochemical surface patterning under extremely mild conditions. Micropatterned azide/benzaldoxime-surfaces were prepared by microcontact printing of a heterobifunctional cyclooctyne oxime ...
Arlinghaus, Heinrich F   +6 more
core   +1 more source

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