Fast dye salts provide fast access to azidoarene synthons in multi-step one-pot tandem click transformations

This study examined whether commercially available diazonium salts could be used as efficient aromatic azide precursors in one-pot multi-step click transformations. Seven different diazonium salts, including Fast Red RC, Fast Blue B, Fast Corinth V and Variamine Blue B were surveyed under aqueous click reaction conditions of CuSO4/Na ascorbate catalyst with 1:1 t-BuOH/H2O solvent. Two-step tandem reactions with terminal alkyne and diyne co-reactants led to 1,2,3-triazole products in 66-88% yields, while three-step tandem reactions with trimethylsilyl-protected alkyne and diyne co-reactants led to 1,2,3-triazole products in 61-78% yields. (C) 2011 Elsevier Ltd. All rights reserved.