Facile One-Pot Synthesis of Monosubstituted 1-Aryl-1H-1,2,3-triazoles from Arylboronic Acids and Prop-2-ynoic Acid (=Propiolic Acid) or Calcium Acetylide (=Calcium Carbide) as Acetylene Source

The synthesis of monosubstituted 1-aryl-1H-1,2,3-triazoles was achieved in a one-pot reaction from arylboronic acids and prop-2-ynoic acid or calcium acetylide (=calcium carbide), respectively, as a source of acetylene, with yields ranging from moderate to excellent (Scheme 1, Table 2). The reaction conditions were successfully applied to arylboronic acids, including analogs with various functionalities. Unexpectedly, the 1,2,3-triazole moiety promoted a regioselective hydrodebromination (Scheme 2).