Ferrocene-containing tetrahydropyridazines via domino chemistry

Since its discovery over 70 years ago, ferrocene has played a pivotal role in nearly every facet of synthetic chemistry, spanning materials science to medicinal chemistry. The unique properties of ferrocene and its derivatives have unsurprisingly made them privileged structures in asymmetric catalysis, the synthesis of biologically active compounds, and components for organoelectronics. In this work, we present a straightforward method for synthesizing ferrocene-based tetrahydropyridazines via a one-pot, base-catalyzed domino condensation of 4-chloro-1-ferrocenylbutan-1-one with monosubstituted hydrazines. Methanol was identified as the optimal solvent for reactions with arylhydrazines, while benzene yielded the best results for reactions involving alkylhydrazines.