Synthesis of 2-substituted benzofurans from o-iodophenols and terminal alkynes with a recyclable palladium catalyst supported on nano-sized carbon balls under copper- and ligand-free conditions
We have developed a one-step synthesis of benzofurans from o-iodophenol and various terminal alkynes, by using Pd catalyst supported on nano-sized carbon balls (NCB) under copper- and ligand free conditions. This recyclable catalyst could be reused more than 5 times in the same heteroannulation reaction. The results have demonstrated that diverse 2-substituted benzofurans with tolerant functional groups can be prepared simply and conveniently under these conditions.