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: Computational studies suggest that the square planar geometry of the palladium is critical to favor the reductive elimination process required for the formation of the oxepine products.
Abstract: 2-Alkenylphenols react with allenes, upon treatment with catalytic amounts of Pd(II) and Cu(II), to give benzoxepine products in high yields and with very good regio- and diastereoselectivities. This contrasts with the results obtained with Rh catalysts, which provided chromene-like products through a pathway involving a β-hydrogen elimination step. Computational studies suggest that the square planar geometry of the palladium is critical to favor the reductive elimination process required for the formation of the oxepine products.
62 citations
TL;DR: Alkenes undergoes insertion into the five-membered ring azanickelacyclic intermediate, and subsequent reductive elimination gives 3-substituted 3,4-dihydroisoquinolin-1(2H)-ones.
Abstract: 1,2,3-Benzotriazin-4(3H)-ones react with 1,3-dienes in the presence of a nickel(0)/phosphine complex to give a variety of 3,4-dihydroisoquinolin-1(2H)-ones. Oxidative insertion of nickel(0) into the triazinone moiety prompts extrusion of dinitrogen to give a five-membered ring azanickelacyclic intermediate. Subsequent insertion of 1,3-dienes into the nickel−carbon bond followed by allylic amidation affords 3,4-dihydroisoquinolin-1(2H)-ones. Alkenes also undergo insertion into the five-membered ring azanickelacyclic intermediate, and subsequent reductive elimination gives 3-substituted 3,4-dihydroisoquinolin-1(2H)-ones.
61 citations
TL;DR: A new ruthenium(ii)-catalyzed electrooxidative [4+2] annulation of primary benzylic alcohols with internal alkynes is described, which enables benzyLic alcohols as weakly directing group precursors to access isocoumarins via multiple C-H functionalization.
61 citations
TL;DR: A palladium-catalyzed intermolecular [4 + 1] annulation pathway for N-phenoxyacetamides with aldehydes to form 1,2-benzisoxazoles was reported in this article.
Abstract: We report a palladium-catalyzed intermolecular [4 + 1] annulation pathway for N-phenoxyacetamides with aldehydes to form 1,2-benzisoxazoles. By activating the C–H bonds ortho to phenol-derived O–N bonds, the method enables the simultaneous construction of C–C and CN bonds in 1,2-benzisoxazoles with the O–N bonds intact. The method has been successfully applied to the synthesis of active pharmaceutical intermediates, such as risperidone.
61 citations
TL;DR: An efficient MgI2-catalyzed annulation between donor-acceptor cyclopropane and N-tosylaziridinedicarboxylate to access highly substituted 2H-furo[2,3-c]pyrrole bearing two rings and four stereocenters, including one quaternary carbon stereocenter, has been developed.
Abstract: An efficient MgI2-catalyzed annulation between donor–acceptor cyclopropane and N-tosylaziridinedicarboxylate to access highly substituted 2H-furo[2,3-c]pyrrole bearing two rings and four stereocenters, including one quaternary carbon stereocenter, has been developed. This methodology can be used for the synthesis of biologically active compounds like IKM-159. This work also offers an insight into the mechanism of the annulation process.
61 citations