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.

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.

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.

One-pot Synthesis of Pyrazolone Sulfones by Iodine-catalyzed Sulfenylation of Pyrazolones with Aryl Sulfonyl Hydrazides Followed by Oxidation in Water

2018 ◽  
Vol 15 (3) ◽  
pp. 380-387
Author(s):  
Xia Zhao ◽  
Xiaoyu Lu ◽  
Lipeng Zhang ◽  
Tianjiao Li ◽  
Kui Lu
Keyword(s):  
Double Bond ◽  
Efficient Method ◽  
Room Temperature ◽  
Sulfonyl Chloride ◽  
Antibacterial Activities ◽  
Oxidation Reactions ◽  
Reaction Conditions ◽  
One Pot ◽  
X Ray ◽  
Amide Form

Aim and Objective: Pyrazolone sulfones have been reported to exhibit herbicidal and antibacterial activities. In spite of their good bioactivities, only a few methods have been developed to prepare pyrazolone sulfones. However, the substrate scope of these methods is limited. Moreover, the direct sulfonylation of pyrazolone by aryl sulfonyl chloride failed to give pyrazolone sulfones. Thus, developing a more efficient method to synthesize pyrazolone sulfones is very important. Materials and Method: Pyrazolone, aryl sulphonyl hydrazide, iodine, p-toluenesulphonic acid and water were mixed in a sealed tube, which was heated to 100°C for 12 hours. The mixture was cooled to 0°C and m-CPBA was added in batches. The mixture was allowed to stir for 30 min at room temperature. The crude product was purified by silica gel column chromatography to afford sulfuryl pyrazolone. Results: In all cases, the sulfenylation products were formed smoothly under the optimized reaction conditions, and were then oxidized to the corresponding sulfones in good yields by 3-chloroperoxybenzoic acid (m-CPBA) in water. Single crystal X-ray analysis of pyrazolone sulfone 4aa showed that the major tautomer of pyrazolone sulfones was the amide form instead of the enol form observed for pyrazolone thioethers. Moreover, the C=N double bond isomerized to form an α,β-unsaturated C=C double bond. Conclusion: An efficient method to synthesize pyrazolone thioethers by iodine-catalyzed sulfenylation of pyrazolones with aryl sulfonyl hydrazides in water was developed. Moreover, this method was employed to synthesize pyrazolone sulfones in one-pot by subsequent sulfenylation and oxidation reactions.

π-Facial Selectivity in 1,3-Dipolar Cycloaddition Reactions of α-Methylidene-γ-lactone Substituted by 4-Methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl Group in γ-Position

2002 ◽  
Vol 67 (3) ◽  
pp. 353-364 ◽  
Author(s):  
Petr Melša ◽  
Ctibor Mazal
Keyword(s):  
Double Bond ◽  
Carboxylic Acid ◽  
Nitrile Oxide ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Enantiomerically Pure ◽  
Nitrile Imine ◽  
Facial Selectivity ◽  
Excellent Selectivity

Diastereoselectivity of 1,3-dipolar cycloaddition reactions of benzyl azide, diazomethane, a nitrile oxide and a nitrile imine to α-methylidene-γ-lactone dipolarophile was effectively controlled by a bulky γ-substituent, 4-methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl in γ-position of the dipolarophile. The dipoles added from the less hindered face of the double bond with an excellent selectivity. Enantiomerically pure dipolarophile was prepared from the easily available (S)-5-oxotetrahydrohydrofuran-2-carboxylic acid.

Reactions of 4-Pyrones with Azomethine Ylides as a Chemo­selective Method for the Construction of Multisubstituted Pyrano[2,3-c]pyrrolidines

Synthesis ◽  
2021 ◽  
Author(s):  
Dmitrii L. Obydennov ◽  
Vyacheslav D. Steben’kov ◽  
Konstantin L. Obydennov ◽  
Sergey A. Usachev ◽  
Vladimir S. Moshkin ◽  
...  
Keyword(s):  
Double Bond ◽  
Ring Opening ◽  
Azomethine Ylides ◽  
Azomethine Ylide ◽  
Dipolar Cycloaddition ◽  
Computational Studies ◽  
Carbon Double Bond ◽  
Reactivity Indexes ◽  
Reaction Proceeds

Abstract4-Pyrones bearing electron-donating and electron-withdrawing groups react with nonstabilized azomethine ylides to form pyrano[2,3-c]pyrrolidines in moderate to good yields. The reaction proceeds chemoselectively as a 1,3-dipolar cycloaddition of the azomethine ylide at the carbon–carbon double bond of the pyrone activated by the electron-withdrawing substituent. The reactivity of 4-pyrones toward azomethine ylides was rationalized by computational studies with the use of reactivity indexes. The pyrano[2,3-c]pyrrolidine moiety could be modified, for example by a ring-opening transformation under the action of hydrazine to provide pyrazolyl-substituted pyrrolidines.

The Solvent Effect on H2O2 Generation at Room Temperature Ionic Liquid|Water Interface

ChemPhysChem ◽  
2021 ◽  
Author(s):  
Marcin Wojciech Opallo ◽  
Justyna Kalisz ◽  
Wojciech Nogala ◽  
Wojciech Adamiak ◽  
Mateusz Gocyla ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Solvent Effect ◽  
Liquid Water ◽  
Room Temperature ◽  
Room Temperature Ionic Liquid ◽  
Water Interface ◽  
H2o2 Generation

scholarly journals Dichloro(η6-p-cymene)(P,P-diphenyl-N-propyl-phosphinous amide-κP)ruthenium(II)

Molbank ◽  
10.3390/m1217 ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. M1217
Author(s):  
Rebeca González-Fernández ◽  
Pascale Crochet ◽  
Victorio Cadierno
Keyword(s):  
Ir Spectroscopy ◽  
Elemental Analysis ◽  
Title Compound ◽  
Room Temperature ◽  
Toluene Solution ◽  
Catalytic Behavior ◽  
Multinuclear Nmr

The title compound, i.e., [RuCl2(η6-p-cymene)(PPh2NHnPr)] (2), was obtained in a 71% yield by reacting a toluene solution of the chlorophosphine complex [RuCl2(η6-p-cymene)(PPh2Cl)] (1) with two equivalents of n-propylamine at room temperature. The aminophosphine complex 2 was characterized by elemental analysis, multinuclear NMR (31P{1H}, 1H and 13C{1H}) and IR spectroscopy. In addition, its catalytic behavior in the hydration of benzonitrile was briefly explored.

1,3-Dipolar cycloadditions of Arylcarbonitrile Oxides and Diaryl Nitrilimines with Some 2-Arylmethylene-1,3-Indanediones; regiochemistry of the Reactions

2003 ◽  
Vol 2003 (4) ◽  
pp. 204-207 ◽  
Author(s):  
Sarra Boudriga ◽  
Mohiedinne Askri ◽  
Rafik Gharbi ◽  
Mohamed Rammah ◽  
Kabula Ciamala
Keyword(s):  
Ring Closure ◽  
Dipolar Cycloaddition ◽  
Dipolar Cycloadditions

Ring-closure reaction affording spiroisoxazolines and spiropyrazolines via a 1,3-dipolar cycloaddition between the title compounds, occurs with high regioselectivity.

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