1, 3-Dipolar cycloaddition reactions are very useful in synthetic organic chemistry. One of them is the Huisgen reaction [1], which was recently improved and named" Click Chemistry" by Sharpless et al.[2] This consists in a cycloaddition reaction between an azide and a terminal alkyne. The regioselectivity of this reaction, controlled by the introduction of catalytic quantities of copper (I), allows the exclusive formation of a 1, 4-disubstituted 1, 2, 3- ...