03588nas a2200169 4500008004100000245013700041210006900178260000800247490000600255520282600261653010203087100002303189700002203212700002403234700002903258856013103287 2017 eng d00aHeterogeneously catalyzed domino synthesis of 3-indolylquinones involving direct oxidative C-C coupling of hydroquinones and indoles0 aHeterogeneously catalyzed domino synthesis of 3indolylquinones i cMAY0 v23 a
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A domino synthesis of 3-indolylquinones was achieved successfully via direct oxidative C–C coupling of hydroquinones with indoles over Ag2O and Fe3O4/povidone–phosphotungstic acid (PVP–PWA) catalysts using H2O2 in tetrahydrofuran at room temperature. Ag2O catalyzed the in situ oxidation of hydroquinone and 3-indolylhydroquinone intermediates, whereas ferrite solid acid, Fe3O4/PVP–PWA, with a 1:4:1 ratio of Fe3O4, PVP, and PWA, catalyzed the activation of quinones. The efficiency of this catalytic domino approach was established by a broad scope of substrates involving a variety of hydroquinones and quinones to give high yields (81–97%) of 3-indolylquinones. Fe3O4/PVP–PWA was separated magnetically, whereas simple filtration could separate Ag2O, both of which could be recycled several times without losing their activities.

10aCarbonyl compounds (organic); Electron microscopy; Fourier-transform spectroscopy; Redox reaction1 aKamble, Sumit, B.;1 aVyas, Praneet, P.1 aJayaram, Radha, V.;1 aRode, Chandrashekhar, V. uhttps://library.ncl.res.in/content/heterogeneously-catalyzed-domino-synthesis-3-indolylquinones-involving-direct-oxidative-c-c