Metallacycle Expansion and Annulation: Access to Tetrazolo‐Fused Osmacycles by Reaction of Cyclic Osmium Carbyne with Sodium Azide

Abstract

Main observation and conclusionThe reaction of a cyclic osmacarbyne complex with sodium azide led to the formation of a ring expansion‐annulation product, a unique tetrazole annulated polycyclic metallacycle. The reaction proceeds by insertion of a nitrogen atom into the metal carbon triple bond and the second azide participating in the [2+3] cycloaddition. The successful isolation and characterization of metalla‐azirine complex and metallapyridinium derivative strongly validated the mechanism for the formation of the title complex. The work demonstrates a new strategy to enrich the varieties of aza‐metallacyclic species.