Divergent copper-catalyzed syntheses of 3-carboxylpyrroles and 3-cyanofurans from <i>O</i>-acetyl oximes and β-ketoesters/nitriles
作者:Wilfrido E. Almaraz-Ortiz、Aldahir Ramos Orea、Oscar Casadiego-Díaz、Agustín Reyes-Salgado、Arturo Mejía-Galindo、Rubén O. Torres-Ochoa
DOI:10.1039/d2ra04938d
日期:——
The reaction between O-acetyl oximes and β-ketoesters/nitriles catalyzed by copper generated polysubstituted pyrroles and furans, respectively, under redox–neutral reaction conditions. Using this protocol, pyrroles or furans could be obtained simply by choosing an appropriate activemethylene compound. Although both transformations occur essentially under the same reaction conditions, control experiments
Reactions of Diphenyl(phenylethynyl)selenonium Salts with Active Methylene Compounds and Amides: First Isolation of Oxyselenuranes [10-Se-4(C3O)] as a Reaction Intermediate
The reaction of the diphenyl(phenylethynyl)selenonium triflate 1a with active methylene compounds 5 and t-BuOK in THF gave furan derivatives 6. The [10-Se-4(C3O)] selenuranes 8a and 8b could be isolated from the reactions with benzoylacetonitrile 5f and with 1,3-indandione 5g, respectively, as reaction intermediates. The structures of the selenuranes 8 were elucidated by X-ray crystallography and Se-77 high-resolution solid-state NMR spectroscopy. The selenuranes 8 underwent ligand coupling on standing at room temperature or refluxing in chloroform and gave the furan derivatives 6 and the ring-opened product 9. Similarly, the reaction of 1a with benzamide 13a and pivalamide 13d in the presence of NaH in THF afforded oxazole derivatives 14.