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: An efficient iodine-mediated oxidative annulation of aryl acetylenes-arylethenes-aromatic ketones with 1,2-diamines for the synthesis of pyrazines and regioselective synthesis of quinoxalines is presented.
72 citations
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TL;DR: A ruthenium(II) complex derived from the electron-deficient aromatic carboxylic acid 3-(F3C)C6H4CO2H proved to be a highly efficient catalyst for dehydrative alkyne annulation by NH-free hydroxamic acids in water.
Abstract: A ruthenium(II) complex derived from the electron-deficient aromatic carboxylic acid 3-(F3C)C6H4CO2H proved to be a highly efficient catalyst for dehydrative alkyne annulation by NH-free hydroxamic acids in water. The C–H/N–OH functionalization occurred with excellent positional selectivity as well as ample substrate scope, setting the stage for effective intermolecular alkenylations of hydroxamic acids. Detailed mechanistic studies were suggestive of a kinetically relevant C–H metalation by carboxylate assistance along with subsequent migratory alkyne insertion, reductive elimination, and intramolecular oxidative addition.
72 citations
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TL;DR: Cp*CoIII -catalyzed highly regioselective mono- and bis-annulation of arylamides with 1,3-diynes using N-OMe as an internal oxidant is demonstrated, demonstrating atom-economical transformation that tolerates many functional groups.
Abstract: Cp*CoIII -catalyzed highly regioselective mono- and bis-annulation of arylamides with 1,3-diynes using N-OMe as an internal oxidant is demonstrated. This atom-economical transformation does not require any external oxidant and tolerates many functional groups. Various symmetrical and unsymmetrical heterocycles (homo and hetero) are accessed with predictable regio- and chemoselectivity.
72 citations
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TL;DR: The first stereoselective annulation reaction between α-cyano-1,4-diketones and ynals, mediated by catalytic amounts of a triazolium salt precatalyst and cocatalytic amount of a weak carboxylate base, is disclosed.
71 citations
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TL;DR: A convergent and highly stereocontrolled synthesis of amphidinolide E (1) has been accomplished as discussed by the authors, which features a highly diastereoselective BF3·Et2O promoted [3+2] annulation reaction between aldehyde 3 and allylsilane 4 to afford substituted tetrahydrofuran 2.
Abstract: A convergent and highly stereocontrolled synthesis of amphidinolide E (1) has been accomplished. The synthesis features a highly diastereoselective (>20:1) BF3·Et2O promoted [3+2] annulation reaction between aldehyde 3 and allylsilane 4 to afford substituted tetrahydrofuran 2.
71 citations