Synthesis of 1,2,3-Triazole 5-Chloroisatin Derivatives via Copper-Catalyzed 1,3-Dipolar Cycloaddition Reactions

A facile and simple protocol for the ‘Click' cycloaddition of organic azides with N-propargylchloroisatine catalyzed by CuI, produces in good yields novel of 1,4-disubstituted 1,2,3-triazoles were obtained. Compared to the uncatalyzed cycloaddition, the yields are significantly improved in the presence of CuI as catalyst, without alteration of the selectivity. The regio- and stereochemistry of the cycloadducts has been corroborated by 1H, 13C NMR spectroscopy.