The development of efficient methods for the synthesis of new organic com-pounds with useful properties, most of which belong
to the class of nitrogen-containing heterocycles, is one of the fundamental tasks of synthetic organic chemistry. The report
discusses one of the strategies currently being developed for the formation of monocyclic, ortho-fused and bridged heterocyclic
systems, based on carbenoid-mediated generation of azapolyene intermediates and their subsequent pericyclic, pseudopericyclic or
nucleophile-initiated cyclizations.1,2 The high synthetic potential of the proposed approach is due to the wide range and synthetic
availability of the starting compounds, as well as to the high reac-tivity of the azapolyene intermediates themselves, which under
mild conditions can form small strained rings, can involve stable benzoid aromatic systems in the cyclization process, and also can
react with weak nucleophiles as cyclization initiators.