Cu-Catalyzed Huisgen Cycloaddition of Sulfonyl Azides ‘on Water∏

Significance

A ‘green∏ and practical method for the Huisgen cycloaddition of water-insoluble sulfonyl azides with alkynes ‘on water∏ is reported. The reaction takes place at room temperature with the simple catalyst system CuX/PhSMe. Interestingly, in contrast to the present catalytic system, use of other ligands than PhSMe led to the formation of amides in the presence of water (S. Chang et al. J. Am. Chem. Soc. 2005, 127, 16046). Various solvents were screened, but water afforded the best yields. The reaction proceeds with high regioselectivity and tolerates considerable substrate scope.