Indoledione-indole

A review of the indoledione-indole rearrangement has appeared. The photoirradiation of l-ethoxy-2-phenylindole in methanol has been shown to afford 3- and 6-ethoxy-2-phenylindoles. ... 

Nonetheless, this stoichiometric methodology was successfully applied by others for the syntheses of a variety of complex indole derivatives. For instance, Katritzky utilized this chemistry to obtain benzotriazolyl-substituted indoles, valuable intermediates in the synthesis of fused and polycyclic indole-derived structures [244,245]. Shvartsberg used Castro s protocol for the assembly of benz[g]indolediones [246], whereas the synthesis of pharmacologically important 1-aminoindole derivatives was reported by Prikhod ko [247, 248]. 

---