Results 11 to 20 of about 8,043 (225)

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

open access: yesBeilstein J Org Chem
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 ...
Fernández I.
europepmc   +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

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

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

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

Intramolecular Cycloaddition of Imines of Cysteine Derivatives

open access: yesMolecules, 1998
Azomethine ylides were generated from Schiffs bases of S-allylcysteine methyl ester and their intramolecular 1,3-dipolar cycloadditions were studied. These reactions led to the synthesis of thieno[3,4-b]pyrrole derivatives in good yield.
Teresa M. V. D. Pinho e Melo   +2 more
doaj   +1 more source

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