Vyacheslav Diev - Carbonyl Ylide Cycloadditions to C,C-Double Bonds of Methylenecyclopropanes.

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      Publication Details (including relevant citation   information):

      Eur.   J. Org. Chem.,   2005, 593-599


      The carbonyl ylide 1,3-dipoles generated by dirhodium   tetraacetate-catalyzed decomposition from   1-diazo-5-phenylpentane-2,5-dione (4) and   1-(1-acetylcyclopropyl)-2-diazo-ethanone (5)   cycloadd to substituted   methylenecyclopropanes2ae and   bicyclopropylidene (3) to give substituted   mono-, di-, and trispirocyclopropanated   8-oxabicyclo[3.2.1]octan-2-ones 7,   8, and 11 and   7-oxabicyclo[2.2.1]heptan-2-ones 10 and   12 in 6–75 % yields with different regio- and   stereoselectivities. The structures of the two isomeric   cycloadducts endo- and exo-10d  formed from the carbonyl ylide derived from 5  and methyl 2-chloro-2-(cyclopropylidene)acetate   (2d) were confirmed by X-ray crystal structure   analyses. (Diphenylmethylene)cyclopropane and   trans-3-methylenecyclopropane-1,2-dicarboxylate (diethyl   ester of Feist’s acid) did not undergo such cycloadditions, while   methylenecyclobutane (13) afforded a mixture of   [3+2] and [2+1] cycloadducts 14 and   15 in 28 and 29 % yields, respectively. The   scope and limitations of these cycloadditions as well as the   influence of different factors upon their regio- and   stereoselectivities are discussed.

      Address (URL): http://onlinelibrary.wiley.com/doi/10.1002/ejoc.200400601/abstract