Weakly Coordinating <i>tert</i>-Amide-Assisted Ru(II)-Catalyzed Synthesis of Azacoumestans via Migratory Insertion of Quinoid Carbene: Application in the Total Synthesis of Isolamellarins
Souradip Sarkar, Rajarshi Samanta
Abstract
-amide-directed straightforward method was developed for the synthesis of azacoumestans using the corresponding azaheterocycle derivatives and diazonaphthoquinones under cheap Ru(II)-catalyzed conditions. The reaction proceeds via migratory insertion of quinoid carbene and subsequent Brønstead acid-mediated cyclization. The optimized C2-selective method offered a wide scope of important azaheterocycles. Bioactive natural products like isolamellarins A and B were synthesized via the developed protocol. Preliminary mechanistic studies highlighted the probable mechanistic pathway.
Topics & Concepts
ChemistryCarbeneAmideCatalysisCombinatorial chemistryScope (computer science)Insertion reactionStereochemistryOrganic chemistryProgramming languageComputer scienceCatalytic C–H Functionalization MethodsCyclopropane Reaction MechanismsOxidative Organic Chemistry Reactions