Effective and Transition-Metal-Free Construction of Disubstituted, Trisubstituted 1,2,3-NH-Triazoles and Triazolo Pyridazine via Intermolecular 1,3-Dipolar Cycloaddition Reaction

2018 ◽  
Vol 3 (2) ◽  
pp. 703-708 ◽  
Author(s):  
Hassan. A. Swarup ◽  
Kemparajegowda ◽  
Kempegowda Mantelingu ◽  
Kanchugarkoppal. S. Rangappa
Keyword(s):  
Transition Metal ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
Metal Free ◽  
Free Construction

scholarly journals SET activation of nitroarenes by 2-azaallyl anions as a straightforward access to 2,5-dihydro-1,2,4-oxadiazoles

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dong Zou ◽  
Lishe Gan ◽  
Fan Yang ◽  
Huan Wang ◽  
Youge Pu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Experimental Evidence ◽  
Radical Anion ◽  
Reaction Pathway ◽  
Cycloaddition Reaction ◽  
Electron Donors ◽  
Ring Closure ◽  
Computational Studies ◽  
Metal Free ◽  
Radical Coupling

AbstractThe use of nitroarenes as amino sources in synthesis is challenging. Herein is reported an unusual, straightforward, and transition metal-free method for the net [3 + 2]-cycloaddition reaction of 2-azaallyl anions with nitroarenes. The products of this reaction are diverse 2,5-dihydro-1,2,4-oxadiazoles (>40 examples, up to 95% yield). This method does not require an external reductant to reduce nitroarenes, nor does it employ nitrosoarenes, which are often used in N–O cycloadditions. Instead, it is proposed that the 2-azaallyl anions, which behave as super electron donors (SEDs), deliver an electron to the nitroarene to generate a nitroarene radical anion. A downstream 2-azaallyl radical coupling with a newly formed nitrosoarene is followed by ring closure to afford the observed products. This proposed reaction pathway is supported by computational studies and experimental evidence. Overall, this method uses readily available materials, is green, and exhibits a broad scope.

Transition metal-free construction of trinuclear N-fused hybrid scaffolds by double nucleophilic aromatic substitution under microwave irradiation

2019 ◽  
Vol 21 (24) ◽  
pp. 6590-6593 ◽  
Author(s):  
Pham Duy Quang Dao ◽  
Ho-Jin Lim ◽  
Chan Sik Cho
Keyword(s):  
Transition Metal ◽  
Microwave Irradiation ◽  
Nucleophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Metal Free ◽  
Green Construction ◽  
Free Construction ◽  
Hybrid Scaffolds

A green construction of trinuclear N-fused hybrid scaffolds by transition metal-free double C(sp2)–N coupling of 2-(2-bromoaryl)- and 2-(2-bromovinyl)benzimidazoles with 2-aminoazoles under microwave irradiation has been developed.

1,3-Dipolar Cycloadditions Involving Allenes: Synthesis of Five-Membered Rings

2020 ◽  
Vol 23 (27) ◽  
pp. 3064-3134 ◽  
Author(s):  
Ana L. Cardoso ◽  
Maria I.L. Soares
Keyword(s):  
Transition Metal ◽  
Cycloaddition Reaction ◽  
Building Blocks ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Relevant Research ◽  
Dipolar Cycloadditions ◽  
Recent Developments ◽  
Synthetic Equivalent ◽  
Metal Catalyzed

The 1,3-dipolar cycloaddition reaction is a powerful and versatile strategy for the synthesis of carbocyclic and heterocyclic five-membered rings. Herein, the most recent developments on the [3+2] cycloaddition reactions using allenes acting either as dipolarophiles or 1,3-dipole precursors, are highlighted. The recent contributions on the phosphine- and transition metal-catalyzed [3+2] annulations involving allenes as substrates are also covered, with the exception of those in which the formation of a 1,3-dipole (or synthetic equivalent) is not invoked. This review summarizes the most relevant research in which allenes are used as building blocks for the construction of structurally diverse five-membered rings via [3+2] annulation reactions.

Phosphorus-containing polymers from THPS. VII. Synthesis of phosphorus-containing trialkynes and their metal-free 1,3-dipolar cycloaddition reaction with azidated soybean-oil

2016 ◽  
Vol 18 (5) ◽  
pp. 1278-1286 ◽  
Author(s):  
Gang Guo ◽  
Jian Sun ◽  
Chen Zhao ◽  
Yun Liu ◽  
Cheng-Mei Liu
Keyword(s):  
Soybean Oil ◽  
Cycloaddition Reaction ◽  
Environmentally Friendly ◽  
Dipolar Cycloaddition ◽  
Metal Free ◽  
Phosphorus Containing

A novel hydrolysis-resistant trialkyne, namely tris(prop-2-yn-1-yloxy methyl)phosphane oxide (TPOPO), was prepared from an environmentally friendly tetrakis(hydroxymethyl)phosphonium sulfate (THPS).

Transition‐Metal Free Construction of Isoquinoline‐fused Triazines Containing Alkenyl C−X Bonds

2019 ◽  
Vol 361 (6) ◽  
pp. 1230-1235 ◽  
Author(s):  
Xiao Cheng ◽  
Xia Cao ◽  
Shuang‐Jing Zhou ◽  
Bao‐Gui Cai ◽  
Xiang‐Kui He ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Free ◽  
Free Construction

Base-mediated 1,3-dipolar cycloaddition of pyridinium bromides with bromoallyl sulfones: a facile access to indolizine scaffolds

2020 ◽  
Vol 18 (42) ◽  
pp. 8694-8701
Author(s):  
Chetna Jadala ◽  
Velma Ganga Reddy ◽  
Namballa Hari Krishna ◽  
Nagula Shankaraiah ◽  
Ahmed Kamal
Keyword(s):  
Transition Metal ◽  
Dipolar Cycloaddition ◽  
Metal Free

A mild, transition-metal-free strategy has been described for the construction of substituted indolizines by 1,3-dipolar cycloaddition of pyridinium bromides with bromoallyl sulfones in the presence of a base.

Iodine(III)-Catalyzed Formal [2 + 2 + 1] Cycloaddition Reaction for Metal-Free Construction of Oxazoles

2017 ◽  
Vol 19 (10) ◽  
pp. 2506-2509 ◽  
Author(s):  
Takuma Yagyu ◽  
Yusuke Takemoto ◽  
Akira Yoshimura ◽  
Viktor V. Zhdankin ◽  
Akio Saito
Keyword(s):  
Cycloaddition Reaction ◽  
Metal Free ◽  
Free Construction

scholarly journals Modification of Biologically Active Plant Metabolites Via the Transition Metal Catalyzed Reactions

2013 ◽  
Vol 15 (3) ◽  
pp. 175 ◽  
Author(s):  
E.E. Shults
Keyword(s):  
Transition Metal ◽  
Heck Reaction ◽  
Cycloaddition Reaction ◽  
Biologically Active ◽  
Dipolar Cycloaddition ◽  
Plant Metabolites ◽  
Click Reactions ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

Developed by the author’s research laboratory methods of functionalization of some plant metabolites or their derivatives, viz., the eudesmane-type methylenelactones, diterpene and morphinane alkaloids, furanolabdanoids, and coumarins, using the transition metal catalyzed reactions, are reviewed. The activity<br />of linear methylene lactone of the eudesmane type in the Heck reaction are analyzed. It is shown that the outcome of the Heck reaction is significantly influenced by the structure of methylidenelactone. The Pd-catalyzed arylation of isoalantolactone with arylhalogenides or 6-bromodeoxyvasicinone occurred with<br />formation mainly of cross-coupling products with the (E) - configuration of the double bond. Synthesis of halogen derivatives of lappaconitine, tetrahydrothebaine and dihydrothebaine-hydroquinone and investigation of in the Heck or Sonogashira reactions gave the possibility for obtaining of new alkaloid derivatives with additional substituents in the aromatic rings. Homocoupling reaction or Sonogashira crosscoupling reaction of 5´- ethynyllappaconitine are used for synthesis of dimeric alkaloids of aconitane types. Pd-catalyzed amination of 2-(1,3-dibromoprop-2-ylidene)oreoselone and the transformations of oreoselone triflate, upon the action of palladium compounds allowed us to accomplish new modifications of linear furocoumarins. The method of enyne cycloisomerization of <em>ω</em>-alkynylfurans catalyzed with Au(III) was successfully obtained in the transformations of furanolabdanoids. The copper(I) salts catalyzed 1,3-dipolar cycloaddition reaction of azides to terminal alkynes belongs to the group of click-reactions was used in the synthesis of macrocyclic structures of labdane diterpenoids. The copper-catalyzed 1,3-dipolar cycloaddition reaction of 2 - azidooreoselone with various alkynes yielded diverse 2-(1,2,3-triazolyl)furocoumarins. The advantages of transition metal catalyzed reactions to the transformations of plant metabolites and its derivatives shown the possibility of introduction of several bioisosteric groups, and other fragments providing additional interactions and selectivity of binding with receptors and enzymes.

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