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

Abstract

A sequential copper-catalyzed, one-pot, click reaction-intramolecular 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 C-C-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. The sequential copper-catalyzed synthesis of heterocycles with [6,6], [6,7], [6,8], and [6,9]ring-fused triazoles and the palladium-catalyzed synthesis of pentacyclic derivatives are explored. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.