Results 41 to 50 of about 7,931 (260)

Kinetic and Thermodynamic Approaches for the Efficient Formation of Mechanical Bonds [PDF]

open access: yes, 2008
Among the growing collection of molecular systems under consideration for nanoscale device applications, mechanically interlocked compounds derived from electrochemically switchable bistable [2]rotaxanes and [2]catenanes show great promise. These systems
Aprahamian, Ivan   +7 more
core   +1 more source

Azetidinylideneketenimines as a Multimodal Synthetic Platform: Coordination Chemistry and Cycloaddition‐Triggered Transformations

open access: yesAngewandte Chemie, EarlyView.
Cross‐coupling/homologation sequence between a stable three‐membered‐ring carbene and isocyanides enables facile and rapid access to novel methyleneketenimines and the first bis(methyleneketenimine). Reactivity studies gave rise to the first methyleneketenimine‐transition metal complexes, unique multimodal reactivity ranging from CO2, isocyanate ...
Taichi Koike   +3 more
wiley   +2 more sources

Asymmetric 1,3-Dipolar Cycloadditons of Stabilized Azomethine Ylides with Nitroalkenes [PDF]

open access: yes, 2014
This review highlights the biological importance of many polysubstituted nitro-prolines and -pyrrolidines. Their preparation using asymmetric 1,3-dipolar cycloadditions of azomethine ylides with nitroalkenes using diastereoselective and enantioselective ...
Nájera, Carmen, Sansano, Jose M.
core   +2 more sources

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

open access: yes, 2015
The 1,3-dipolar cycloaddition of acyclic 2-diazo-1,3-dicarbonyl compounds (DDC) and thioketones preferably occurs with Z,Econformers and leads to the formation of transient thiocarbonyl ylides in two stages.
Holleman   +8 more
core   +4 more sources

Synthesis of Spiroisoxazolines by 1,3-Dipolar Cycloaddition

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 ...
Peter Ertl   +3 more
doaj   +1 more source

Concerted [4 + 2] and Stepwise (2 + 2) Cycloadditions of Tetrafluoroethylene with Butadiene: DFT and DLPNO-UCCSD(T) Explorations. [PDF]

open access: yes, 2020
Tetrafluoroethylene and butadiene form the 2 + 2 cycloadduct under kinetic control, but the Diels-Alder cycloadduct is formed under thermodynamic control. Borden and Getty showed that the preference for 2 + 2 cycloaddition is due to the necessity for syn-
Houk, KN   +4 more
core  

X=Y–ZH compounds as potential 1,3-dipoles. Part 64: Synthesis of highly substituted conformationally restricted and spiro nitropyrrolidines via Ag(I) catalysed azomethine ylide cycloadditions [PDF]

open access: yes, 2008
1,3-Dipolar reactions of imines of both acyclic and cyclic α-amino esters with a range of nitroolefins using a combination of AgOAc or Ag2O with NEt3 are described.
Albert   +51 more
core   +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

Photo-induced 1, 3-Dipolar Cycloaddition Reaction of Aziridinedicarboximide

open access: yesChemical and Pharmaceutical Bulletin, 1969
Cycloaddition reaction of N-(p-methoxyphenyl)-1-benzyl-2, 3-aziridinedicarboximide (8) with dimethyl acetylenedicarboxylate (3) was not effected thermally, but under irradiation it resulted in a formation of 1 : 1-cycloadducts, I (9), II (17), and III (34), and a 1 : 2-cycloadduct IV (38).
SADAO OIDA, EIJI OHKI
openaire   +2 more sources

Theoretical Study of 1,3-Dipolar Cycloadditions Regioselectivity of Benzyl Azide with Glycosyl-O Acetylene Using Density Functional Theory (DFT)

open access: yesOrbital: The Electronic Journal of Chemistry, 2017
A theoretical study of 1,3-cycloaddition has been carried out using density functional theory (DFT) methods at the B3LYP/6-31G* level. The regioselectivity of the reaction have been clarified through different theoretical approaches: Case of a Two-Center
Adib Ghaleb   +5 more
doaj   +1 more source

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