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Two facile approaches have been developed for the synthesis of fused benzimidazole-diazepinones and dibenzimidazole-diazepines based on an Ugi/de-protection/cyclization strategy and the hydroamination of an alkyne. This efficient cascade process afforded the target compounds in good yields via a facile one-pot operation involving the formation of a new C–N bond.

A novel copper-catalyzed microwave-promoted propargyl­ation/alkyne oxacyclization/isomerization cascade for the synthesis of 2-methylfuro[3,2-c]coumarins has been developed. This reaction provides furo[3,2-c]coumarins in moderate to good yields (≤82%) from readily available 4-hydroxycoumarins and terminal propargyl acetates as starting materials. Interestingly, by changing the solvent from dimethyl sulfoxide to 1,2-dichloroethane, the isomeric series of 2-meth­ylene-2,3-dihydrofuro[3,2-c]coumarins were obtained in good to acceptable yields (≤85%).

A fused benzimidazole–imidazole scaffold was designed and synthesized using a facile procedure involving deprotection and cyclization reactions. The acidic conditions and high yields for the benzimidazole ring closure allow potential application of this efficient methodology for the design and synthesis of a range of bioactive compounds.

A convenient one-pot protocol is developed for the synthesis of the title compounds (V) and (VII) through Ugi reaction/deprotection/cyclization strategy followed by an intramolecular nucleophilic substitution reaction.