1,2-Diamination of Alkenes via 1,3-Dipolar Cycloaddition with Azidium Ions or Azides

We describe two new methods for the 1,2-diamination of alkenes. First, either an azidium ion (ArN═N⁺═NAr) undergoes 1,3-dipolar cycloaddition with an alkene to give a 1,2,3-triazolinium ion directly, or an intramolecular azide-alkene cycloaddition followed by N-benzylation provides the same. Second, hydrogenation of the 1,2,3-triazolinium ion over Raney Ni excises the central N atom and gives the 1,2-diamine. The stereochemistry of the alkene is usually, but not always, preserved in the 1,2-diamine.