1,3-Dipolar cycloaddition reactions of monocyclic aziridines with dimethyl 1-cyclobutene-1,2-dicarboxylate

1994 ◽  
Vol 72 (10) ◽  
pp. 2108-2117 ◽  
Author(s):  
Kiyoshi Matsumoto ◽  
Hirokazu Iida ◽  
Takane Uchida ◽  
Yoshimi Yabe ◽  
Akikazu Kakehi ◽  
...  
Keyword(s):  
Ring Opening ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Thermally Induced ◽  
X Ray ◽  
Orbital Interactions ◽  
Dipole Interactions

The thermally induced [2 + 3] cycloadditions of certain monocyclic aziridines to dimethyl 1-cyclobutene-1,2-dicarboxylate are described. The structures of the resulting bicyclic adducts were established unambiguously by X-ray analyses. The stereochemistries of the [2 + 3] adducts were interpreted in terms of dipole–dipole interactions and secondary orbital interactions. In certain cases an initial thermal conrotatory ring opening of the cyclobutene to 2,3-di(methoxycarbonyl)-1,3-butadiene precedes the [2 + 3] cycloaddition, affording the unexpected pyrrolidine adducts 12a and 12b. The structures and stereochemistries of the latter established by X-ray analysis strongly suggest that secondary orbital interactions between the phenyl and ester groups control and stereochemistry of the reactions.

1,3-Dipolar Cycloadditions of a Chiral Oxazolidinone With Nitrones and Nitrile Oxides

1995 ◽  
Vol 48 (9) ◽  
pp. 1511 ◽  
Author(s):  
SG Pyne ◽  
J Safaei-G ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Hydrogen Atmosphere ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
The Novel ◽  
X Ray ◽  
Dipolar Cycloadditions ◽  
Nitrile Oxides ◽  
Exocyclic Methylene

The 1,3-dipolar cycloaddition reactions of the chiral oxazolidinone (1) and nitrones are highly regioselective and only 5,5-disubstituted isoxazolidine adducts are formed. These reactions occur under equilibrating conditions to give the more stable adducts that result from addition to the exocyclic methylene of (1) from the sterically more hindered π-face. The endo adducts are generally thermodynamically favoured. In one case the novel azetidine (21) was formed from the treatment of the adduct (4a) with palladium hydroxide on carbon under a hydrogen atmosphere. The major adducts from the reaction of (1) and nitrile oxides (16a,b) had the expected stereochemistry, addition of the 1,3-dipole having occurred from the less hindered π-face of the exocyclic methylene of (1). The stereochemistry of many of these products has been elucidated by single-crystal X-ray structural determinations.

1,3-Dipolar cycloaddition reactions of 7-alkenyl- or 7-alkynyl-8-azidomethyltheophyllines

1988 ◽  
Vol 53 (2) ◽  
pp. 319-328 ◽  
Author(s):  
Dušan Hesek ◽  
Alfonz Rybár ◽  
František Považanec ◽  
Augustin Martvoň ◽  
Jaroslav Kováč
Keyword(s):  
Thionyl Chloride ◽  
Sodium Azide ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Thermally Induced ◽  
Intramolecular Cycloaddition ◽  
Phosphorus Tribromide

8-Azidomethyltheophillines XI-XIV, containing dipolarophilic alkenyl or alkynyl (i.e. allyl, 2-butenyl, cinnamyl, and 2-propynyl) groups in position 7, undergo thermally induced 1,3-dipolar intramolecular cycloaddition under formation of 7-substituted 1,3-dimethyl-2,4-dioxo-1,2,3,4,6,6a,7,11-octahydro(1,2,3)triazolo[1’,5’:1,2]pyrazino[5,4-f]purines XV-XVII and 1,3-dimethyl-2,4-dioxo-1,2,3,4,6,11-hexahydro(1,2,3)triazolo[1’,5’:1,2]pyrazino[5,4-f]purine (XVIII), respectively. The compounds were synthesized starting from 8-hydroxymethyltheophilline (I) which was alkylated to give 7-alkenyl- and 7-alkynyl-8-hydroxymethyltheophillines III-VI and these were converted into the corresponding 8-halogenomethyl derivatives VII-X by treatment with thionyl chloride or phosphorus tribromide. Reaction of VII-X with sodium azide afforded the 8-azidomethyl derivatives XI-XIV.

scholarly journals Synthesis of Octahydropyrano[2,3-d]Pyrimidine Derivatives via Tetrahydropyrano[3,2-e][1,3]Thiazolo[3,2-a]Pyrimidine and 2,6-Dichlorobenzonitrile Oxide

2018 ◽  
Vol 42 (6) ◽  
pp. 317-319
Author(s):  
Qing Zeng ◽  
Demin Ren ◽  
Aiting Zheng ◽  
Xiaofang Li
Keyword(s):  
Ring Opening ◽  
Crystallographic Analysis ◽  
Dipolar Cycloaddition ◽  
Pyrimidine Derivatives ◽  
X Ray ◽  
Moderate Yield

N1-substituted octahydro-1 H-pyrano[2,3- d]pyrimidines derivatives were prepared in moderate yield by the reaction of methyl [(4a RS,5 SR,10a RS)-5-aryl-2-oxo-3,4,4 a,10 a-tetrahydro-2 H,5 H-pyrano[3,2- e][1,3]thiazolo[3,2- a]pyrimidin-8(9 H)-ylidene]acetate and 2,6-dichorobenzonitrile oxide via a domino 1,3-dipolar cycloaddition/ring-opening/dethionation process. The structures of the products were characterised by spectroscopic and X-ray crystallographic analysis.

Diastereoselective Propionitrile Oxide Cycloaddition Reactions With Some γ-Substituted α-Methylene-γ-butyrolactones

1993 ◽  
Vol 46 (9) ◽  
pp. 1401 ◽  
Author(s):  
SM Pereira ◽  
GP Savage ◽  
GW Simpson ◽  
RJ Greenwood ◽  
MF Mackay
Keyword(s):  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
X Ray ◽  
X Ray Crystallography ◽  
Relative Stereochemistry

A number of γ-substituted α-methylene-γ-butyrolactone derivatives underwent 1,3-dipolar cycloaddition with propionitrile oxide to give spiro Δ2-isoxazolines. The reaction proceeded regiospecifically and with high diastereoselectivity. The products of anti addition predominated. The regiochemistry of addition and relative stereochemistry of the products were determined by a combination of n.O.e ., HETCOR and DOUBTFUL n.m.r. experiments. The assignment was confirmed in one case by X-ray crystallography.

scholarly journals Regio- and Stereoselectivity in the 1,3-Dipolar Cycloaddition Reactions of Isoquinolinium Ylides with Cyclopenta[a]acenaphthylen-8-ones

Synlett ◽  
2020 ◽  
Vol 31 (17) ◽  
pp. 1691-1695
Author(s):  
Issa Yavari ◽  
Parisa Ravaghi ◽  
Maryam Safaei ◽  
Jasmine Kayanian
Keyword(s):  
Dft Calculations ◽  
Cycloaddition Reaction ◽  
Crystallographic Analysis ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Diastereoselective Synthesis ◽  
X Ray

AbstractA convenient regio- and diastereoselective synthesis of functionalized 5a,5b-dihydro-5H,13H-naphtho[1′′,8′′:4′,5′,6′]pentaleno[1′:3,4]pyrrolo[2,1-a]isoquinolin-5-ones via 1,3-dipolar cycloaddition reaction of 8H-cyclopenta[a]acenaphthylen-8-ones with carbonyl-stabilized isoquinolinium N-ylides, is described. Based on DFT calculations at b3lyp/6-311+g(d,p) level of theory, a nonconcerted mechanism is proposed to explain the regioselectivity of this reaction. The structure of a typical product was confirmed by X-ray crystallographic analysis.

scholarly journals Synthesis of Dispiro[Indeno[1,2-b]Quinoxaline-11,3′-Pyrrolizine-2′,2″-[1,3] Thiazolo[3,2-a]Pyrimidine Via Cycloaddition Reactions

2018 ◽  
Vol 42 (9) ◽  
pp. 453-455 ◽  
Author(s):  
Demin Ren ◽  
Xiaolian Hu ◽  
Yulin Huang ◽  
Xiaofang Li
Keyword(s):  
Cycloaddition Reaction ◽  
Crystallographic Analysis ◽  
Azomethine Ylide ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
X Ray

The 1,3-dipolar cycloaddition reaction of ethyl 5-aryl-2-(2-methoxy-2-oxoethylidene)-7-methyl-3-oxo-2,3-dihydro-5 H-[1,3]thiazolo[3,2- a] pyrimidine-6-carboxylate and azomethine ylide, which was generated in situ by the reaction of 11 H-indeno[1,2- b]quinoxalin-11-one and L-proline, afforded novel 6″ethyl 1′-methyl 5″aryl-7″methyl-3″oxo-5’,6’,7’,7a′-tetrahydro-1' H,3″ H,5″ H-dispiro[indeno[1,2- b]quinoxaline-11, 3 ‘-pyrrolizine-2’,2″-[1,3]thiazolo[3,2- a]pyrimidine-1’,6″-dicarboxylates in good yields. The structures of all the products were characterised thoroughly by NMR, IR and HRMS together with X-ray crystallographic analysis.

1,3-Dipolar cycloaddition reactions of phthalic anhydrides with an azomethine ylide

2015 ◽  
Vol 2 (6) ◽  
pp. 705-712 ◽  
Author(s):  
Hugo Santos ◽  
Amy Distiller ◽  
Asha M. D'Souza ◽  
Quentin Arnoux ◽  
Jonathan M. White ◽  
...  
Keyword(s):  
Ring Opening ◽  
Cycloaddition Reaction ◽  
Azomethine Ylide ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Ring Opening Reaction ◽  
Phthalic Anhydrides

A series of phthalic anhydrides underwent a 1,3-dipolar cycloaddition reaction with N-benzylazomethine ylide to produce unstable spiro(isobenzofuran-1,5′-oxazolidin)-3-ones, which underwent a subsequent reductive ring-opening reaction to afford 1(3H)-isobenzofuranones.

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