Results 61 to 70 of about 25,988 (120)

3‐Tocopherylisoxazolines by [2+3] Cycloaddition

European Journal of Organic Chemistry, 2004
AbstractNew isoxazoline derivatives of α‐tocopherol (1), the main component of vitamin E, were synthesized in a facile, two‐step sequence consisting of nitration followed by 1,3‐dipolar cycloaddition. 5‐Nitromethyl‐γ‐tocopheryl acetate (3), obtained from the cheap α‐tocopheryl acetate (2) by direct nitration in one step, acted as the nitrile oxide ...
Thomas Rosenau, Christian Adelwöhrer, Andreas Hofinger, Kurt Mereiter, Paul Kosma   +4 more
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[2 + 2] Cycloaddition of Ynamides to Construct 3-Aminocyclobutenones

Organic Letters, 2022
An efficient Tf2NH-catalyzed [2 + 2] cycloaddition of ynamides under mild conditions has been developed. Within short reaction times, various ynamides are transformed into the corresponding 3-aminocyclobutenones in good to excellent yields. This is the first example for the metal-free intermolecular [2 + 2] self-cycloaddition of ynamides.
Yanru Wang, Mengjun Hu, Lixia Ding, Yanan Wang, Xiao-Na Wang, Junbiao Chang   +5 more
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Polymerization by [3 + 2]‐cycloaddition

Die Makromolekulare Chemie, 1988
AbstractThe reaction of hexafluoroacetone azine (1) with dienes 13a–d was used to synthesize polymers 14a–d of a new type with diazabicylooctanediyl units in the main chain. The influence of the structure of the diolefins on the solubility of these polymers was investigated.
Oskar Nuyken, Gerhard Maier, Klaus Burger   +2 more
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Tandem [4+2]/[3+2] Cycloadditions of Nitroalkenes

Chemical Reviews, 1996
Insofar as one of the fundamental objectives of organic synthesis is the construction of complex molecules from simpler ones, the importance of synthetic efficiency becomes immediately apparent and has been well-recognized.1 The increase in molecular complexity2 that necessarily accompanies the course of a synthesis provides a guide (and a measure) of ...
Scott E., Denmark, Atli, Thorarensen
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Dearomative Indole (3 + 2) Cycloaddition Reactions

Journal of the American Chemical Society, 2014
A diastereoselective (3 + 2) dearomative annulation of 3-substituted indoles with α-haloketones has been developed. Significant regiochemical control was observed. This methodology provides easy access to highly functionalized cyclopenta- or cyclohexa-fused indoline compounds, which are common structures of many natural products.
Hui, Li, Russell P, Hughes, Jimmy, Wu
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Synthesis of trifluoromethylated pyrazolidines by [3 + 2] cycloaddition

Organic & Biomolecular Chemistry, 2017
[3 + 2] cycloaddition between trifluoromethylated N -acylhydrazones and nitroolefins in the presence of potassium hydroxide and Bu 4 NI is developed to afford potentially bioactive trifluoromethylated pyrazolidines.
Xiansha Peng, Danfeng Huang, Ke-Hu Wang, Yalin Wang, Juanjuan Wang, Yingpeng Su, Yulai Hu   +6 more
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Polymerization by [3 + 2] cycloaddition, 3. Polyimides

Die Makromolekulare Chemie, 1989
AbstractThe reaction between hexafluoroacetone azine and bis(bicyclo[2.2.1]hept‐5‐en‐2,3‐dicarboximide)s (5 and 6) (dinadimides) (mole ratio 1:1) yields polymers with number‐average molar masses between M̄n = 1700 and M̄n = 5700 depending on the reactants. The possible isomeric structures of the polymers are discussed in detail.
Oskar Nuyken, Gerhard Maier, Klaus Burger, Angels Serra i Albet   +3 more
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Theoretical Studies on [3 + 2]‐Cycloaddition Reactions

ChemInform, 2006
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
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Diazotrifluoroethyl Radical in Photoinduced [3 + 2] Cycloadditions

Organic Letters
Herein we report a photocatalytic [3 + 2] cyclization reaction enabled by redox processes. Starting from hypervalent iodine(III) reagent and N-benzylidenealkylamines, this protocol facilitates the efficient synthesis of diverse 5-trifluoromethyl-1,2,4-triazoles, providing a direct and practical route to these heterocyclic scaffolds in moderate to ...
Li-Ping Tu, Jia-Yun Lai, Cong An, Jia-Lei Jiang, Yong-Li Wang, Han-Ping Mu, Yong-Zheng Chen, Wen-Yong Han   +7 more
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Organotransition metal [3+2] cycloaddition reactions

Coordination Chemistry Reviews, 2002
Abstract The review, covering the literature of roughly the last three decades, describes the [3+2] cycloaddition reactions of metalla dipolarophiles MX with organic 1,3-dipoles, and of metalla 1,3-dipoles, MXY and XMY, with organic dipolarophiles.
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