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: New annulation reactions of azomethine ylides are reported and amino acids react with aldehydes that are linked to a pronucleophile to provide rapid access to polycyclic ring systems.
Abstract: New annulation reactions of azomethine ylides are reported. Amino acids react with aldehydes that are linked to a pronucleophile (e.g. an indole subunit) to provide rapid access to polycyclic ring systems. Simple amines can also be used in place of amino acids.
103 citations
TL;DR: The reusable sulfoximine directing-group-assisted Ru(II)-catalyzed chemo- and regioselective ortho-C-H alkenylation of arenes and heteroarenes with acrylates and α,β-unsaturated ketones/vinyl sulfone is shown.
Abstract: The reusable sulfoximine directing-group-assisted Ru(II)-catalyzed chemo- and regioselective ortho-C–H alkenylation of arenes and heteroarenes with acrylates and α,β-unsaturated ketones/vinyl sulfone is shown. The N-aroyl sulfoximine undergoes annulation with diphenylacetylene, delivering isoquinolinones and methyl phenyl sulfoxide. The present protocol is successfully employed for the synthesis of the EP3 receptor antagonist analogue.
103 citations
TL;DR: The detailed mechanisms, role of NHC, and origin of chemo‐ and stereoselectivity of these kinds of reactions were illustrated to provide valuable insights for rational design of new NHC‐catalyzed cycloaddition/annulation reactions with high selectivities.
Abstract: The developments of theoretical studies on NHC-catalyzed [n + 2] (n = 2, 3, 4) and other cycloaddition/annulation reactions have been summarized in this review. The detailed mechanisms, role of NHC, and origin of chemo- and stereo-selectivity of this kind of reactions were illustrated to provide valuable insights for rational design of new NHC-catalyzed cycloaddition/annulation reactions with high selectivities. Moreover, computational and theoretical methods commonly used in the researches were also mentioned to open the door for deeply exploring the general principle of NHC-catalyzed reactions in theory.
102 citations
TL;DR: Cp*-free cobalt-catalyzed alkyne annulations by C-H/N-H functionalizations were accomplished with molecular O2 as the sole oxidant, providing step-economical access to the anticancer topoisomerase-I inhibitor 21,22-dimethoxyrosettacin.
Abstract: Cp*-free cobalt-catalyzed alkyne annulations by C-H/N-H functionalizations were accomplished with molecular O2 as the sole oxidant. The user-friendly oxidase strategy proved viable with various internal and terminal alkynes through kinetically relevant C-H cobaltation, providing among others step-economical access to the anticancer topoisomerase-I inhibitor 21,22-dimethoxyrosettacin. DFT calculations suggest that electronic effects control the regioselectivity of the alkyne insertion step.
102 citations
TL;DR: A novel and efficient copper or nickel catalyzed highly selective denitrogenative annulation of vinyl azides with aryl acetaldehydes has been developed and the present reaction conditions are mild, neutral, and very simple without any additives.
102 citations