The reactions of alkynes and a-nitro-olefines with methylazide and phenylazide was studied. In contrast to known reactions with alkynes which are non-regioselective, methylazide and phenylazide react regiospecifically with a-nitro-olefines and give only one type of triazole after elimination of HN02. These reactions are very useful synthetic approaches to 1,2,3 triazoles.Les 1,2,3 triazoles ont fait I'objet de nombreux