ZnO-nanoparticles as an efficient catalyst for the synthesis of tetrasubstituted cyclopentadienones using sulfonoketenimides and enaminoesters

A convenient and efficient approach to the synthesis of substituted cyclopentadienes is reported based on the reaction of sulfonoketenimides and enaminoesters in good yield. In these reactions, sulfonoketenimides is produced from the reaction of terminal alkynes and sulfonyl azides in the presence of copper iodide and enaminoesters is prepared via the reaction of dialkyl acetylenedicarboxylates and primary amines in the presence of ZnO-nanoparticles.