Transannulation of Pyridotriazoles with Naphthoquinones and Indoles: Synthesis of Benzo[<i>f</i>]Pyrido[1,2‐<i>a</i>]Indoles and Indolizino[3,2‐<i>b</i>]indoles
Deepa Rawat, Subbarayappa Adimurthy
Abstract
Abstract Ruthenium catalysed denitrogenative transannulation of pyridotriazoles with naphthoquinones provided the transannulated benzo[ f ]pyrido[1,2‐ a ]indoles derivatives in good to excellent yields. While pyridotriazoles with indoles in presence of PivOH and oxone yield indolizino[3,2‐ b ]indoles under metal‐free conditions. Quinone annulation proceeds through ruthenium‐carbenoid intermediate while indole annulation may proceed via a diazo‐pyridinium intermediate. Control experiments suggest that both the transformations follow the ionic mechanism. magnified image
Topics & Concepts
ChemistryAnnulationCarbenoidIndole testPyridiniumRutheniumYield (engineering)QuinoneStereochemistryTotal synthesisBicyclic moleculeDiazoMedicinal chemistryOrganic chemistryCatalysisRhodiumMaterials scienceMetallurgyCatalytic C–H Functionalization MethodsCyclopropane Reaction MechanismsSynthesis and Reactivity of Heterocycles