Reactions of diphenylcyclopropenone with 1,3-dipoles

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Section: -3 Bond Cleavage and 13-dipolar Additions Of 2-(2-thieny1)mentioning

confidence: 99%

“…However, 2-aryl-3-carboalkoxy and 2-aryl-3-cyanoaziridines underwent quite different reactions than 2-aryl-3-ar~~laziridines with certain dipolarophiles (12). Also the nature of the Nsubstituent in 2-aryl-3-aroylaziridines had a profound effect on the course of the reaction with aryl isothiocyanates (5).…”

mentioning

confidence: 98%

Synthesis and cycloaddition reactions of 2-(2-thienyl)aziridines

Lown¹,

Matsumoto²

1970

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“…The assignment of the geometry is based upon the 'H NMR data (Table 1) and the well-documented observation that a ring proton or ester methyl protons are shielded by a cis-vicphenyl group (8,9). Furthermore, the chemical shifts of Ha, H,, and the ester methyl protons have values in accord with those of the reported pyrrolidine adducts (10,11). The stereochemistry of the adducts was unambiguously confirmed in the cases of 3 a and 3 c by their single crystal X-ray diffraction analyses (Fig.…”

Section: Resultsmentioning

confidence: 81%

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

Matsumoto¹,

Iida²,

Uchida³

et al. 1994

KIYOSHI MATSUMOTO, HIROKAZU IJDA, TAKANE UCHIDA, YOSHIMI YAEIE, AIUKAZU KAKEHI, and J. WILLIAM LOW. Can. J. Chem. 72,2108Chem. 72, (1994.The thermally induced [2+3] cycloadditions of certain monocyclic aziridines to dimethyl 1-cyclobutene-l,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 dipole4ipole 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. [Traduit par la rkdaction]

“…Controlled dehydrogenation of pyrrolidine 19 with p-chloranil (9) gave initially the pyrroline 20. Aroylazomethine Ylides with lmidodipolarophiles lmine dipolarophiles are not normally very reactive, however when polarized by an adjacent group, say arylsulfonyl, we have found their 1,3-dipolar reactivity to be substantially enhanced (5).…”

Section: Aroylazomethine Ylides and Aroylalkynesmentioning

confidence: 99%

Reactions of Functionalized 1,3-Dipoles

Lown¹,

Landberg²

1974

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A new synthetic approach to the formation of 5-5,5-6,s-5-5, and 6-5-6 fused heterocycles employing cycloadditions with functionalized dipoles is described and its scope and utility explored through representative examples. The regiochemistry and stereochen~istry of the additions is established by specific deuterium labelling, n.m.r. spectroscopy, and by chemical means.On dCcrit une nouvelle approche synthetique a la formation des hetCrocycles condenses 5-5, 5-6, 5-5-5 et 6-5-6; la generalit6 et I'utilite de cette methode impliquant des cycloadditions de dipoles fonctionnalises est examine par l'intermidiaire d'exemples reprisentatifs. L a regiosClectivitC et la stereochimie des additions est Btablie i I'aide de marquage par le deuterium de faqon specifique, par r.m.n. et par des moyens chimiques.[ basic reaction to a scheme for the preparation of thermal decomposition of 3-aroylaziridines in linked heterocycles (2) as illustrated in eq. 2 via acetonitrile (3, 4) and in their reaction with consecutive condensation and 1,3-dipolar addi-p-nitrosophenols (4) when 3,5-dihydro-2H-pyrtion. A similar general synthetic scheme for the rolo[3,4-d]oxazoles were obtained in good yield.preparation of fused ring heterocycles would be a valuable extension of the general cycloaddition principle. One approach we wish to explore in this paper is the scope of the reactions of 1,3-dipoles bearing additional functionality (i.e. besides their basic 4n electron reactive system) to form bicyclic heterocycles, as shown in eq. 3. The additional functionalities f and g on the 1,3-dipole and dipolarophile, respectively, should give the potential second fused five-or sixmembered ring provided the reaction has the desired regiochemistry and stereochemistry. Indications of the usefulness of this approach had been obtained during an examination of the O = C H --COArOur initial approach to systematize these findings has been to examine the reaction of aroylazomethine ylides (generated by the thermal electrocyclic cleavage of aziridines) with a range of suitably functionalized dipolarophiles). Exploratory reactions of azomethine oxides (nitrones) are also discussed in this context. For personal use only.