A novel and convenient strategy for the synthesis of phthalazines from an aryne precursor

A novel three-step entry toward phthalazine derivatives has been elaborated. A strategy based on a sequential acyl-alkylation/diazo transfer reaction/Diaza-Wittig reaction led to the desired analogues in moderate to good yields from an aryne precursor. Various aryl groups were introduced on the annulated pyridazine, moreover the presence of an ester group allows further modifications.