1,3-dipolar cycloaddition of C-benzoyl-N-phenylnitrone with furan derivatives. Anomalous dehydrogenation of cycloadducts with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone

1980 ◽  
Vol 45 (12) ◽  
pp. 3546-3556 ◽  
Author(s):  
Lubor Fišera ◽  
Ján Leško ◽  
Miloslava Dandárová ◽  
Jaroslav Kováč
Keyword(s):  
Double Bond ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
Furan Derivatives ◽  
Dipolar Cycloadditions

C-Benzoyl-N-phenylnitrone reacted with 2-R-substituted (R = phenyl, CH2OH, CH2OCOCH3, CH2SH) furan derivatives at 55 °C by a 1,3-dipolar cycloaddition reaction to the unsubstituted furan double bond to give mono- and bisadducts. 2,5-Dimethylfuran afforded monoadduct only. Dehydrogenations of monoadducts of 5-R-2-phenyl-3-benzoyl-3a,6a-dihydrofuro[3,2-c]isoxazolines with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone proceeded anomalously at 60 °C: dehydrogenation followed by electrocyclic opening afforded the corresponding ketonitrones. This method of dehydrogenation offers a new preparation of nitrones and further exemplifies the exploitation of products of 1,3-dipolar cycloadditions for synthetic purposes.

scholarly journals Huisgen [3 + 2] Dipolar Cycloadditions of Phthalazinium Ylides to Activated Symmetric and Non-Symmetric Alkynes

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4416
Author(s):  
Vasilichia Antoci ◽  
Costel Moldoveanu ◽  
Ramona Danac ◽  
Violeta Mangalagiu ◽  
Gheorghita Zbancioc
Keyword(s):  
Reaction Time ◽  
Comparative Study ◽  
Cycloaddition Reaction ◽  
Environmentally Friendly ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Dimethyl Acetylenedicarboxylate ◽  
Thermal Heating ◽  
Dipolar Cycloadditions ◽  
Methyl Propiolate

We present herein a straightforward and efficient pathway for the synthesis of pyrrolophthalazine cycloadducts via Huisgen [3 + 2] dipolar cycloaddition reactions of phthalazinium ylides to methyl propiolate or dimethyl acetylenedicarboxylate (DMAD). A thoroughly comparative study concerning the efficiency of synthesis, conventional thermal heating (TH) versus microwave (MW) and ultrasound (US) irradiation, has been performed. The cycloaddition reactions of phthalazinium ylides to methyl propiolate occur regiospecific, with a single regioisomer being obtained. Under conventional TH, the cycloaddition reaction of phthalazinium ylides with DMAD occurs to a mixture of inseparable partial and fully aromatized pyrrolophthalazine cycloadducts, while MW or US irradiation are leading only to fully aromatized compounds, with the reactions becoming selective. A feasible mechanism for formation of fully aromatized compounds is presented. Besides selectivity, it has to be noticed that the reaction setup under MW or US irradiation offer a number of other certain advantages: higher yields, decreasing of the amount of used solvent comparative with TH, decreasing of the reaction time from hours to minutes and decreasing of the consumed energy; consequently, these reactions could be considered environmentally friendly.

Beyond the Alternatives that Switch the Mechanism of the 1,3-Dipolar CyCloadditions from Concerted to Stepwise or Vice Versa: A Literature Review

2016 ◽  
Vol 41 (4) ◽  
pp. 331-344 ◽  
Author(s):  
Seyyed Amir Siadati
Keyword(s):  
Organic Chemistry ◽  
Literature Review ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
Stepwise Mechanism ◽  
Dipolar Cycloadditions ◽  
Catalyst Free ◽  
Number Of Factors ◽  
Reaction Channels ◽  
The 1960S

For several decades, the concerted or stepwise character of the mechanism of the 1,3-dipolar cycloaddition reaction has been one of the most debated issues in the field of organic chemistry. The significance of this problem is due to the fact that in a catalyst-free 1,3-dipolar cycloaddition, when the mechanism switches from concerted to stepwise, the stereospecificity is lost and thus unwanted stereoisomers may emerge. The first proposals about the mechanism of the 1,3-dipolar reaction were due to Huisgen (concerted model) and subsequently by Firestone (two-step diradical channel) in the 1960s. After a decade of debate, most researchers accepted the concerted model for the reaction, but during these years, researchers reported some examples of the stepwise mechanism for catalyst-free 1,3-dipolar cycloadditions. This review attempts to find a number of factors that could influence the reaction channels and switch the mechanism from concerted to stepwise, or vice versa.

Correlation of kinetic data of 1,3-dipolar cycloadditions of C-benzoyl-N-phenylnitrones with the homo energies of furan derivatives

1981 ◽  
Vol 46 (6) ◽  
pp. 1504-1512 ◽  
Author(s):  
Lubor Fišera ◽  
Anton Gáplovský ◽  
Hans-Joachim Timpe ◽  
Jaroslav Kováč
Keyword(s):  
Charge Transfer ◽  
Rate Constants ◽  
Kinetic Data ◽  
Empirical Equation ◽  
Dipolar Cycloaddition ◽  
Charge Transfer Complexes ◽  
Electron Affinities ◽  
Furan Derivatives ◽  
Dipolar Cycloadditions ◽  
Experimental Values

Application of PMO treatment to 1,3-dipolar cycloaddition of C-benzoyl-N-phenylnitrone with furan derivatives is described. Ionization potentials of 2-R-substituted furan derivatives (R = H, CH3, C2H5, CH2OH, CH2OCOCH3, C6H5, CHO) and 2,5-dimethylfurane representing experimental values of the HOMO energies have been determined from energies of the respective charge-transfer complexes with TCNE. Good correlation between IP and k2 rate constants indicates that the reaction is controlled by the LUMO(nitrone)/HOMO(furan deriv.) interaction. Electron affinities of the furan derivatives were determined from IP and energies of π-π* transitions using empirical equation ΔE(π-π*) = IP-EA-450.58 kJ mol-1.

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.

Highly enantioselective catalytic 1,3-dipolar cycloadditions of α-alkyl diazoacetates: efficient synthesis of functionalized 2-pyrazolines

2015 ◽  
Vol 13 (9) ◽  
pp. 2745-2749 ◽  
Author(s):  
Sung Il Lee ◽  
Ka Eun Kim ◽  
Geum-Sook Hwang ◽  
Do Hyun Ryu
Keyword(s):  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
Efficient Synthesis ◽  
Dipolar Cycloadditions

Chiral oxazaborolidinium ion catalyzed 1,3-dipolar cycloaddition reaction of α-substituted diazoacetates gives functionalized 2-pyrazolines in high to excellent enantiomeric ratios.

1,3-Dipolar cycloadditions of ylide of 5-nitro-2-furfurylpyridinium bromide in indolizine synthesis

1982 ◽  
Vol 47 (6) ◽  
pp. 1738-1745 ◽  
Author(s):  
Jarmila Štetinová ◽  
Miloslava Dandárová ◽  
Jaroslav Kováč ◽  
Darina Mesárošová ◽  
Ján Leško
Keyword(s):  
Mass Spectra ◽  
Cycloaddition Reaction ◽  
Ethyl Acrylate ◽  
Dipolar Cycloaddition ◽  
Dimethyl Acetylenedicarboxylate ◽  
Diethyl Maleate ◽  
Dipolar Cycloadditions ◽  
H Nmr

Substituted 3-(5-nitro-2-furyl)indolizines III-X were synthesized by 1,3-dipolar cycloaddition reaction of the ylide II, generated from 5-nitro-2-furfurylpyridinium bromide (I), with acrylonitrile, ethyl acrylate, diethyl maleate, benzalacetophenone, ethyl 3-(5-nitro-2-furyl)acrylate, (5-nitro-2-furfurylidene)acetophenone, β-nitrostyrene and dimethyl acetylenedicarboxylate. The structure of these products is discussed on the basis of their 1H NMR and mass spectra.

Site-selectivity of 1,3-dipolar cycloadditions to 2,3-dimethoxycarbonyl-7-oxabicyclo[2,2,1]heptadiene

1983 ◽  
Vol 48 (11) ◽  
pp. 3144-3153 ◽  
Author(s):  
Lubor Fišera ◽  
František Považanec ◽  
Peter Zálupský ◽  
Jaroslav Kováč ◽  
Dušan Pavlovič
Keyword(s):  
Double Bond ◽  
Solvent Effect ◽  
Title Compound ◽  
Room Temperature ◽  
Dipolar Cycloaddition ◽  
Multiple Bonds ◽  
Dipolar Cycloadditions ◽  
Site Selectivity ◽  
Synthetic Equivalent

Site-selectivity of dipolar cycloaddition to the title compound was studied. Azomethine X afforded a 1 : 1 cycloadduct XI at the deactivated double bond at room temperature; upon thermolysis at 110 °C it afforded the acetylated enamine XIII which was formed via a direct cycloaddition at the mentioned temperature. The cycloaddition course was investigated in various solvents; the enamine XIV formed by solvolysis of XIII was the final product in methanol. Cycloaddition of the title compound to azides, benzoylnitrile N-oxide and C-acetyl-N-phenylnitrilimine furnished the product of cycloreversion instead of the not isolable 1 : 1 cycloadducts. 5-Azido-2-furancarbaldehyde and 4-nitrophenylazide yielded cycloaddition products to both multiple bonds in an approximately 1 : 1 ratio; NH3, tosylazide, benzoylnitrile N-oxide and C-acetyl-N-phenylnitrilimine gave the addition products to the deactivated double bond. The solvent-effect of site-selectivity of 1,3-dipolar cycloaddition was investigated and the title compound was found to be an excellent synthetic equivalent for acetylene and dimethyl butinedioate.

scholarly journals Asymmetric Lewis acid-catalyzed 1,3-dipolar cycloadditions

2008 ◽  
Vol 80 (5) ◽  
pp. 1013-1018 ◽  
Author(s):  
Andrei Bădoiu ◽  
Yasmin Brinkmann ◽  
Florian Viton ◽  
E. Peter Kündig
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Lewis Acids ◽  
Cycloaddition Reaction ◽  
Diels Alder ◽  
Dipolar Cycloaddition ◽  
Dipolar Cycloadditions ◽  
Asymmetric Catalytic ◽  
Aldehydes And Ketones ◽  
Acid Catalyzed

Highly tuned, one-point binding chiral iron and ruthenium complexes selectively coordinate and activate α,β-unsaturated aldehydes and ketones toward asymmetric catalytic Diels-Alder cycloaddition reactions. Here we focus on the application of these transition-metal Lewis acids to asymmetric catalytic 1,3-dipolar cycloaddition reaction between enals and cyclic and acyclic nitrones as well as aryl nitrile oxides to give isoxazolidines and isoxazolines, respectively.

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