Strategy to Construct Functionalized Tetrazepine Derivatives via [4+3] Annulation Reaction of Azomethine Imine with Azadiene Precursor

Tetrazepine derivative exhibits good biological activities.Only a limited method has been devoted to constructing these frameworks to date.Therefore, an efficient and novel way was established for the synthesis of functionalized tetrazepine scaffolds through the cycloaddition reaction of azomethine imine with 1,2-azadiene formed in situ by α-halogeno hydrazones in the presence of KOH.This transformation shows excellent functional group tolerance and substrate scope.