Ring-centered heterocyclic cations and the direct heteroarylation of aromatic and heterocyclic compounds

[GRAPHICS] The protonation of heterocyclic diazotates (attachment adjacent to a nitrog en atom) yields ring-centered heterocyclic carbocations that are highly rea ctive. The carbocations were found to alkylate aromatic and heterocyclic co mpounds, such as benzene, N-methylpyrrole, and 2-aminopyridine, in reaction s that are synthetically useful. This carbocation involvement may serve as a paradigm for the cross-linking of DNA by nitrous acid and the anticancer activity of heterocyclic diazotates.