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 new approach to construct 2,3-disubstituted quinolines is described via Pd-catalyzed oxidative cyclization of o-vinylanilines and alkynes with molecular oxygen.
57 citations
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TL;DR: A wide range of o-alkynylanilines undergo a copper-catalyzed direct C-H/N-H coupling with azoles followed by benzannulation to form the corresponding N-azolylindoles in good yields.
57 citations
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TL;DR: To the authors' knowledge, this is the first example of enantioselective C-H functionalization of polyfluoroarenes with alkenes, and it is claimed that this reaction is also the first to employ bulky chiral N-heterocyclic carbene ligands for nickel catalysts.
Abstract: Chiral polyfluoroarene derivatives are an important scaffold in chemistry. An unprecedented enantioselective C-H alkylation of polyfluoroarenes with alkenes is described. The reaction employs bulky chiral N-heterocyclic carbene (NHC) ligands for nickel catalysts to enable exclusive activation of C-H bonds over C-F bonds and complete endo-selective C-H annulation and excellent enantioselectivity. A wide variety of chiral fluorotetralins, compounds otherwise difficultly accessed but serve as important bioisosteric analogs of both tetralin and heterocycle units for drug design, are expediently synthesized from easily available substrates. To our knowledge, this is the first example of catalytic enantioselective C-H functionalization of polyfluoroarenes.
57 citations
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TL;DR: Fluoren-9-ones and derivatives are readily prepared in good yields by the annulation of in situ generated arynes by 2-haloarenecarboxaldehydes in the presence of a palladium catalyst.
Abstract: Fluoren-9-ones and derivatives are readily prepared in good yields by the annulation of in situ generated arynes by 2-haloarenecarboxaldehydes in the presence of a palladium catalyst.
57 citations
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TL;DR: It is reported that Morita-Baylis-Hillman carbonates from isatins and carbamate-functionalized allyl carbonates could be chemoselectively activated by achiral Lewis basic tertiary amines and chiral iridium complexes, respectively.
Abstract: Asymmetric reactions merging organocatalysis and metal catalysis significantly broaden the scope of organic synthesis. Nevertheless, the accomplishment of stereoselective annulations combining two types of dipole species, independently generated from the activations of organocatalysts and metal complexes, still remains as a challenging task. Now, Morita-Baylis-Hillman carbonates from isatins and carbamate-functionalized allyl carbonates could be chemoselectively activated by achiral Lewis basic tertiary amines and chiral iridium complexes. The zwitterionic allylic ylides and 1,4-π-allyliridium dipoles formed in situ are assembled in a highly stereoselective [4+3] annulation pattern. Similar cooperative catalytic strategy could be applied for the reactions of Morita-Baylis-Hillman carbonates and vinyl aziridines, furnishing an asymmetric [3+3] annulation reaction also with excellent stereocontrol.
57 citations