Oxidative aromatic C-N bond formation: convenient synthesis of N-amino-3-nitrile-indoles via FeBr3-mediated intramolecular cyclization

A variety of functionalized N-amino-3-nitrile-indole derivatives are obtained via an intramolecular hetero-cyclization of 2-aryl-3-substituted hydrazono-alkylnitriles using FeBr3 as a single electron oxidant. This approach allows the N-moiety on the side-chain to be annulated to the benzene ring during the final synthetic step via direct oxidative aromatic C-N bond formation.