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A one-pot copper(II)-catalyzed tandem synthesis of 2-substituted pyrrolo[1,2-b]pyridazin-4(1H)-ones from N-aminopyrroles was developed. This tandem reaction involves a Conrad–Limpach-type reaction, including the thermal condensation of N-aminopyrroles with the carbonyl group of β-oxo esters followed by the cyclization of Schiff base intermediates. Compared to the traditional Conrad–Limpach quinoline synthesis, we herein successfully applied copper(II) as a catalyst in this transformation to furnish 2-substituted pyrrolo[1,2-b]pyridazin-4(1H)-ones for the first time. Most of the substrates bearing electron-donating (EDG) and electron-withdrawing (EWG) groups worked well with this procedure. The corresponding products could be converted directly into diverse pyrrolo[1,2-b]pyridazine for drug discovery and materials science.

A one-pot copper(II)-catalyzed tandem synthesis of 2-substituted pyrrolo[1,2-b]pyridazin-4(1H)-ones from N-aminopyrroles was developed. This tandem reaction involves a Conrad–Limpach-type reaction, including the thermal condensation of N-aminopyrroles with the carbonyl group of β-oxo esters followed by the cyclization of Schiff base intermediates. Compared to the traditional Conrad–Limpach quinoline synthesis, we herein successfully applied copper(II) as a catalyst in this transformation to furnish 2-substituted pyrrolo[1,2-b]pyridazin-4(1H)-ones for the first time. Most of the substrates bearing electron-donating (EDG) and electron-withdrawing (EWG) groups worked well with this procedure. The corresponding products could be converted directly into diverse pyrrolo[1,2-b]pyridazine for drug discovery and materials science.

An efficient tandem method for the annulation of 1-amino-1H-pyrrole-2-amides with various substituted benzaldehydes, heteroaryl aldehydes, alkyl aldehydes or even acetals, promoted by cupric chloride, to synthesize 2-substituted pyrrolo[2,1-f][1,2,4]triazin-4(3H)-ones is reported. This approach provides a useful method for constructing the privileged structure in medicinal chemistry. Electron-donating groups on both partners could accelerate the reaction.

A novel Pd/Cu catalyzed synthesis of pyrrolopyridazines under mild conditions is developed.

An efficient palladium/copper-catalyzed domino reaction was developed to yield functionalized naphthalenes, quinolines, and isoquinolines. The reactions of various substituted 1-phenylprop-2-yn-1-ols containing electron-donating (EDG) and electron-withdrawing (EWG) groups and 1-heteroarylprop-2-yn-1-ols worked well with this procedure. Both electron-rich and -deficient aryl halides were satisfactory substrates for this reaction. This domino benzannulation process involves a Sonogashira cross-coupling reaction, followed by isomerization to a chalcone, and finally an intramolecular condensation reaction.

An efficient palladium/copper-catalyzed domino reaction was developed to yield functionalized naphthalenes, quinolines, and isoquinolines. The reactions of various substituted 1-phenylprop-2-yn-1-ols containing electron-donating (EDG) and electron-withdrawing (EWG) groups and 1-heteroarylprop-2-yn-1-ols worked well with this procedure. Both electron-rich and -deficient aryl halides were satisfactory substrates for this reaction. This domino benzannulation process involves a Sonogashira cross-coupling reaction, followed by isomerization to a chalcone, and finally an intramolecular condensation reaction.