Quantitative characterization of the global electrophilicity pattern of some reagents involved in 1,3-dipolar cycloaddition reactions

Pérez, Patricia; Domingo, Luís R.; Aurell, M. J.; Contreras, Renato

doi:10.1016/s0040-4020(03)00374-0

Cited by 309 publications

(204 citation statements)

References 35 publications

Supporting

Mentioning

193

Contrasting

Unclassified

Order By: Relevance

“…The flux of the CT found at the more favourable TSs is in agreement with the large electrophilic character of the nitrilimine 2g, ω = 1.75 eV, than that of 3-thioxo-[1,2,4]-triazepin-5-one 1-E, ω =1.30 eV. 25 As these cycloadditions have some polar character, and solvent can modify the energies, effect of benzene was considered. In benzene, all species are stabilized between 3 and 8 kcal/mol.…”

Section: (3g-z) Kcal/mol On the Other Hand Formation Of The Regiosimentioning

confidence: 53%

Formation of pyrazol‐1,3,4‐thiadiazoles through 1,3‐dipolar cycloadditions of 3‐thioxo‐[1,2,4]‐triazepin‐5‐one with nitrilimines: an experimental and computational study

Esseffar¹,

Messaoudi²,

Azzouzi³

et al. 2008

J of Physical Organic Chem

View full text Add to dashboard Cite

In this work the results of experimental and computational study of the title compounds and some ancillary compounds are reported. Two bicyclic pyrazol-1,3,4-thiadiazole derivatives were synthesized by reaction between 6-dimethylaminomethylene-3-thioxo-[1,2,4]-triazepin-5-one 1 and several nitrilimines 2a-f to give corresponding spirocycloadducts 3a-f, which undergo a rapid rearrangement leading to the new bicyclic compounds, 4a-f and 5a-f.These obtained bicyclic products were characterized by 1 H and 13 C NMR spectroscopy and finally by X-ray crystallography. Theoretical calculations have been carried out using DFT methods to rationalize the formation of the two new bicyclic compounds. Two reaction types are involved in the formation of the compounds 4a-f and 5a-f. The first one is a 1,3-dipolar cycloaddition reaction between 1 acting as dipolarophile and 2a-f as dipoles. The results indicate that the cycloaddition between 1 and 2g, as model of 2a-c, takes place via a high asynchronous bond-formation process. The regioselectivity obtained from the calculations is in complete agreement with the formation of the unique spirocycloadducts 3a-f. The second reaction leading to the formation of the final products is a domino process that is initiated by the quick and irreversible cleavage in a catalytic acid environment of triazepenic ring. Messaoudi 1975Messaoudi -2003 2 ¤ dedicated to the memory of Tourya El

show abstract

Section: (3g-z) Kcal/mol On the Other Hand Formation Of The Regiosimentioning

confidence: 53%

Formation of pyrazol‐1,3,4‐thiadiazoles through 1,3‐dipolar cycloadditions of 3‐thioxo‐[1,2,4]‐triazepin‐5‐one with nitrilimines: an experimental and computational study

Esseffar¹,

Messaoudi²,

Azzouzi³

et al. 2008

J of Physical Organic Chem

View full text Add to dashboard Cite

show abstract

“…18 In the case of a series of β-carboethoxy-β-nitrostyrenes global electrophilicity is significantly lower (in particular: (1i) = 2.64, (1f) = 2.72, (1g) = 2.93, (1h) = 2.93 eV), but remain in the range typical for the strongly electrophilic dipolarophiles. 19 Notably, these reactions can be considered as polar1,3-dipolar cycloaddition (P-13DC). 20 Detailed analysis of the local electrophilicity indices on the reaction centers of nitroalkenes also revealed that the reaction was determined by the attack of nucleophilic atom of 1,3-dipole to β-position of nitroalkene, similarly as in the reactions of nitroethene with nitrones.…”

Section: Resultsmentioning

confidence: 99%

Efficient synthesis of functionalized 1,2,3-triazoles by catalyst-free 1,3-dipolar cycloaddition of nitroalkenes with sodium azide

Wang¹,

Hu²,

Huang³

et al. 2012

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

Foi desenvolvido um protocolo simples e eficiente para a síntese de derivados de 1,2,3-triazol pela cicloadição 1,3-dipolar de nitroalquenos com azida de sódio, sem a necessidade de catalisador e sob condições brandas.A simple and efficient protocol has been developed for the synthesis of 1,2,3-triazole derivatives by catalyst-free 1,3-dipolar cycloaddition of nitroalkenes with sodium azide under mild conditions. Keywords: 1,2,3-triazoles, 1,3-dipolar cycloaddition, 3-nitrocoumarins, sodium azide, catalyst-free IntroductionFive-membered nitrogen heterocycles play an important role in biological systems. Among these, the 1,2,3-triazoles and their derivatives are of considerable interest as they possess a wide range of biological properties, such as anti-HIV, 1 anti-allergic, 2 anti-fungal, 3 anti-viral 4 and anti-microbial activity. 5 1,2,3-Triazoles are important in pharmacological applications due to its stability toward light, moisture, oxygen, and metabolism in the body. 6 In addition, these moieties are widely applied as photosensitizers, dyes, 7 and commercially employed as anti-corrosive agents 8 in industry. Owing to the importance of these compounds, a variety of methods are known in the literature for the synthesis of pyrazoles, which include the thermal 1,3-dipolar cycloaddition of azide with various alkynes 9 and cycloaddition reactions of terminal alkynes with alkyl azides using Cu(I) as catalyst. 10 In addition, these molecules can also be prepared in one-pot procedure from alkynes with azides. 11 In fact, a straightforward approach to 1,2,3-triazoles is interesting and catalystfree intermolecular 1,3-dipolar cycloaddition azides with electron-deficient alkenes to afford 1,2,3-triazoles, has been the subject of intensive research. 12 Recently, sodium azide has been used as a 1,3-dipole in 1,3-dipolar cycloaddition for the synthesis of 1,2,3-triazoles. 12 Considering the above reports and encouraged by the good results, we envisaged that 1,3-dipolar cycloaddition would be possible between the α-carbonyl-β-aryl analogs of nitroethene with sodium azide, as outlined in Scheme 1. First, the reaction was happened via 1,3-dipolar cycloaddition of nitroalkenes with sodium ion as the key step. Then, elimination of the NaNO 2 and migration of hydrogen atom afford 1,2,3-triazoles. Results and DiscussionCoumarins are important heterocycles widely present in natural products exhibiting a broad range of biological and therapeutic activities and have been the subject of intensive research. 13 Recently, we have demonstrated the usefulness of the catalyst-free intermolecular 1,3-dipolar cycloaddition of 3-nitrocoumarins in the synthesis of functionalized pyrazoles with good yields. 14 We considered that the incorporation of a 1,2,3-triazole heterocyclic unit into 3-nitrocoumarins might provide 1,2,3-triazole derivatives that have important biological and pharmaceutical activities. Thus, we turned our attention to the possible synthesis of 1,2,3-triazoles using 3-nitrocoumarins 1 as dipolarophiles for the electron-po...

show abstract

“…According to Domingo suggestions [27] for these calculations, B3LYP/6-31G(d) theory level was used. In particular, the electronic chemical potentials (l) and chemical hardness (g) were evaluated in terms of one-electron energies of FMO (E HOMO and E LUMO) using the following equations:…”

Section: Calculation Methodsmentioning

confidence: 99%

A reexamination of the molecular mechanism of the Diels–Alder reaction between tetrafluoroethene and cyclopentadiene

Jasiński

2016

Reac Kinet Mech Cat

View full text Add to dashboard Cite

DFT calculation results shed a new light on the mechanism of cycloaddition reaction between tetrafluoroethene and cyclopentadiene. The unique influence of fluorine atoms on the ethylene derivative molecule causes the [2 ? 2] cycloaddition process to take place according to a stepwise, biradical mechanism. At the same time, the competitive and independent path leads to a one-step (and not a twostep, as was once thought) cycloaddition reaction leading to a [2 ? 4] cycloadduct.

show abstract

Quantitative characterization of the global electrophilicity pattern of some reagents involved in 1,3-dipolar cycloaddition reactions

Cited by 309 publications

References 35 publications

Formation of pyrazol‐1,3,4‐thiadiazoles through 1,3‐dipolar cycloadditions of 3‐thioxo‐[1,2,4]‐triazepin‐5‐one with nitrilimines: an experimental and computational study

Formation of pyrazol‐1,3,4‐thiadiazoles through 1,3‐dipolar cycloadditions of 3‐thioxo‐[1,2,4]‐triazepin‐5‐one with nitrilimines: an experimental and computational study

Efficient synthesis of functionalized 1,2,3-triazoles by catalyst-free 1,3-dipolar cycloaddition of nitroalkenes with sodium azide

A reexamination of the molecular mechanism of the Diels–Alder reaction between tetrafluoroethene and cyclopentadiene

Contact Info

Product

Resources

About