An efficient, ligand-free, heterogeneous supported copper hydroxide catalyst for the synthesis of n,n-bicyclic pyrazolidinone derivatives.

Cycloaddition of a variety of azomethine imines with electron-deficient terminal alkynes proceeds smoothly in the presence of a heterogeneous Cu(OH)x—Al2O3 catalyst to give bicyclic pyrazolidinone derivatives in high yields.