(3 + 2) cycloaddition of 2-alkoxynaphthalenes with azaoxyallyl cations: access to benzo[<i>e</i>]indolones.

A reaction between 2-alkoxynaphthalene and an <i>in situ</i> formed azaoxyallyl cation has been reported under ambient reaction conditions. The (3 + 2) cycloaddition reaction followed by aryl C-OMe/C-OEt bond cleavage produces a variety of benzo[<i>e</i>]indolone derivatives. Based on the isolated intermediate from the control experiment and previous results, a possible mechanism has been drawn. Reduction of the N-O bond of the benzo[<i>e</i>]indolone derivative manifests the possibility of further functionalization of the products towards biologically important heterocyclic molecules.