Topic
Annulation
About: Annulation is a research topic. Over the lifetime, 10152 publications have been published within this topic receiving 189701 citations.
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TL;DR: A phosphine-catalyzed [3+2] annulation reaction of α-substituted allenoates with ester-activated α,β-unsaturated imines is reported, which provides new and efficient access to highly functionalized cyclopentenes bearing one all-carbon quaternary center.
60 citations
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60 citations
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TL;DR: Rhodium-catalyzed oxidative annulation reactions of 3-(1H-indol-3-yl)-3-oxopropanenitriles withinternal alkynes with internal alkynes have been developed and some of the 4H-oxepino[2,3,4,5-def]carbazole products exhibit intense fluorescence in the solid state.
60 citations
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TL;DR: From certain substrates, the direct annulation is observed in the titanium-mediated step, which is likely to occur through an olefin metathesis-intramolecular olefination sequence.
Abstract: The dimethyltitanocene methylenation of N-acylamides derived from ortho-vinylanilines, ortho-allylaniline, and ortho-vinylbenzylamine provides the corresponding enamides, which upon exposure to the second generation Grubbs ruthenium catalyst give access to indoles, 1,4-dihydroquinolines, and 1,2-dihydroisoquinolines, respectively. This sequential protocol also allows the synthesis of dihydrobenzoazepines, although the ring-closing metathesis (RCM) step is complicated by the alkene isomerization processes. From certain substrates, the direct annulation is observed in the titanium-mediated step, which is likely to occur through an olefin metathesis−intramolecular olefination sequence.
60 citations
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TL;DR: A Rh-catalyzed C-H/C-H vinylene cyclization adopting vinylene carbonate as a "vinylene transfer" agent achieves the direct annulative π-extension of imidazole- and pyrazole-fused aromatics.
60 citations