Cu(OTf)2 Catalyzed the Reaction of Donor‐Acceptor Cyclopropanes With Salicylaldehyde Phenylhydrazones: Synthesis Polycyclic Tetrahydropyridazines

ABSTRACT A simple method has been developed to prepare tetrahydro‐5H‐chromeno[4,3‐ c ]pyridazin‐5‐ones by reacting donor‐acceptor cyclopropane 1,1‐dieters with salicylaldehyde phenylhydrazones in the presence of Cu(OTf) 2 , yielding moderate results with excellent diastereoselectivity. Moreover, control experiments revealed that the reaction proceeds via a tandem [3 + 3]‐annulation/lactonization mechanism.