An Appealing, Robust Access to Furo-Fused Heteropolycycles

Recently, nitrostilbenes characterized by two different or differently substituted aryl moieties, obtainable from the initial ring-opening of 3-nitrobenzo[b]thiophene with amines, have proved, by means of a stepwise double coupling with phenolic-type bidentate C/O nucleophiles, to be valuable precursors of oxygen-containing heteropolycycles and of fully conjugated systems therefrom via an efficient 6π-electrocyclization and final aromatization. Herein, the methodology is extended, after suitable optimization, to diverse heterophenols to afford new appealing heteropolycyclic systems of potential interest as drug leads. The synthetic results are fully consistent with up-to-date quantomechanical calculations. For some of the new molecules, a significant fluorescence is reported, with a potential for future applications, e.g., in the field of optical devices.