Versatile role of λ3‐iodanes has been identified between the reaction of hydroquinone and β‐enaminones for the synthesis of 5‐acyloxy‐4‐hydroxy indoles. The reaction is proposed to proceed through an intermolecular C−C bond formation, intramolecular cyclization, acyloxylation and 1,4‐acyl migration. The important features of this work include various acyloxylation from λ3‐iodanes and broad functional group tolerance to deliver 34 examples in moderate to good yields.magnified image

Unprecedented chemo- and regioselective synthesis of benzo­[a]­fluorenes and naphthamide-substituted benzo­[a]­fluorenes were constructed from the reaction of (E)-2-aroyl-3-(2-(arylalkynes/alkenes)­aryl)­acrylonitrile scaffolds under metal-free conditions via the activation of nitriles and alkenes, respectively. A tentative reaction mechanism was proposed for this homofunctionalization of nitriles. Control experiments showed that the reaction proceeds via selective nitrile or alkene protonation, depending upon the substrates. Additionally, we demonstrated an alternative expeditious route for the synthesis of disubstituted benzo­[a]­fluorenes in the presence of TfOH alone.