Synthesis of Naphthyridine and Azepine Backbones through Formal [4+3] and [4+2] Annulation via Cascade Ring‐Opening/Cyclization Reaction of 2<i>H</i>‐Azirines
Shahab A. Darbandizadeh, Kamran Amiri, Frank Röminger, Saeed Balalaie
Abstract
Abstract A zinc‐mediated cascade ring‐opening cyclization of 2 H ‐azirines and enolized‐ o ‐alkenylquinoline carbaldehydes for the synthesis of naphthyridine and azepine skeletons has been disclosed. The regioselectivity of the reaction can be switched from a seven‐ to a six‐membered ring by shifting from two‐ to monosubstituted 2 H ‐azirine. This transformation involves the construction of two C=C and C=N double bonds. This report describes 2 H ‐azirine‐dependent cascade annulation in formal [4+3], and [4+2] cyclization reactions.
Topics & Concepts
AzepineAnnulationChemistryRing (chemistry)AzirineCascadeRegioselectivityCascade reactionStereochemistryCombinatorial chemistryCatalysisOrganic chemistryChromatographyCatalytic C–H Functionalization MethodsSynthesis and Catalytic ReactionsCyclopropane Reaction Mechanisms