Results 41 to 50 of about 28,125 (246)

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

1,3-Dipolar Cycloaddition Reactions of Azomethine Ylides with Carbonyl Dipolarophiles Yielding Oxazolidine Derivatives

open access: yesMolecules, 2016
We provide a comprehensive account of the 1,3-dipolar cycloaddition reactions of azomethine ylides with carbonyl dipolarophiles. Many different azomethine ylides have been studied, including stabilized and non-stabilized ylides.
Adam G. Meyer, John H. Ryan
doaj   +1 more source

Isolation of bis(copper) key intermediates in Cu-catalyzed azide-alkyne "click reaction". [PDF]

open access: yes, 2015
The copper-catalyzed 1,3-dipolar cycloaddition of an azide to a terminal alkyne (CuAAC) is one of the most popular chemical transformations, with applications ranging from material to life sciences.
Bertrand, Guy   +3 more
core   +2 more sources

Synthesis of Spiroisoxazolines by 1,3-Dipolar Cycloaddition [PDF]

open access: yesMolecules, 1997
The cycloaddition of the chiral nitrile oxide 1 to 1-R-substituted 3,3-methylene-5,5-dimethyl-2-pyrrolidinones 2 (where R is H, n-butyl-, 1,1-dimethylethoxycarbonyl-, 1-methylethenyl- and acetyl-) proceeds regioselectively under the formation of spiroisoxazolines, namely 7-R-substituted-6-oxo-8,8-dimethyl-1-oxa-2,7-diazaspiro[4,4]non-2-enes 5 and 6 ...
Lubor Fišera   +3 more
openaire   +3 more sources

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

A study on selective transformation of norbornadiene into fluorinated cyclopentane-fused isoxazolines

open access: yesBeilstein Journal of Organic Chemistry, 2021
This work presents an examination of the selective functionalization of norbornadiene through nitrile oxide 1,3-dipolar cycloaddition/ring-opening metathesis (ROM)/cross-metathesis (CM) protocols. Functionalization of commercially available norbornadiene
Zsanett Benke   +2 more
doaj   +1 more source

Ferrocene-derived P,N ligands : synthesis and application in enantioselective catalysis [PDF]

open access: yes, 2013
Due to their unique steric and electronic properties, air-stability and modular structure, chiral hybrid P,N-ferrocenyl ligands play a prominent role in the field of asymmetric catalysis.
Noël, Timothy, Van der Eycken, Johan
core   +1 more source

[4 + 2] Cycloadditions of diphenylketene with a highly substituted 1,3-diene [PDF]

open access: yes, 1987
Diphenylketene (2) undergoes [4 + 2] cycloadditions with the s-cis fixed diene (1) to give the dihydropyran (3) and the cyclohexenone (4)
Heigl, Ulrich W., Mayr, Herbert
core   +1 more source

Arylthio-substituierte Nitrilylide aus der Thermolyse von 4-Arylthio-3-oxazolin-5-onen

open access: yesCHIMIA, 1984
Thermolysis of 4-arylthio- and 4-benzylthio-3-oxazolin-5-ones leads to arylthio- and benzylthio-substituted nitrile ylides, which undergo 1,3-dipolar cycloadditions with reactive dipolarophiles to give 5-membered aza-heterocycles (Schemes 1 and 2).
Peter Wipf, Heinz Heimgartner
doaj   +1 more source

Site-Selective Modification of a Porpholactone—Selective Synthesis of 12,13- and 17,18-Dihydroporpholactones

open access: yesMolecules, 2020
The reaction of meso-tetrakis(pentafluorophenyl)porpholactone with azomethine ylides and nitrones affords pyrrolidine-fused and isoxazolidine-fused dihydroporpholactones that display, respectively, isobacteriochlorin- and chlorin-type UV–Vis spectra ...
Ana F. R. Cerqueira   +5 more
doaj   +1 more source

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