Facile Construction of [6,6]-, [6,7]-, [6,8]-, and [6,9]Ring-Fused Triazole Frameworks by Copper-Catalyzed, Tandem, One-Pot, Click and Intramolecular Arylation Reactions: Elaboration to Fused Pentacyclic Derivatives

A sequential copper-catalyzed, one-pot, click reactionintramolecular direct arylation, which involves two mechanistically distinct reactions (atom-economical click reaction and direct arylation of 1,2,3-triazole), to generate [6,6]-, [6,7]-, [6,8]-, and [6,9]ring-fused triazoles is reported. Furthermore, a unique divergence of reactivity between the fused triazoles prepared from 2-bromobenzyl azide and 2-bromophenylazide that leads to a fused pentacyclic heterocycle for the former and a CC-coupled, biphenyl-fused, tricyclic product for the latter is observed under Pd catalysis. All of the key products have been characterized by single-crystal X-ray crystallography.