Synthesis of benzofurans from terminal alkynes and iodophenols catalyzed by recyclable palladium nanoparticles supported on N,O-dual doped hierarchical porous carbon under copper- and ligand-free conditions

We herein report that a stable and recyclable heterogeneous catalyst, consisting of Pd nanoparticles supported on N , O -dual doped hierarchical porous carbon derived from naturally available and renewable biomass-bamboo shoots, which allows for highly efficient one-pot tandem reaction of o -iodophenols with terminal alkynes to synthesize biologically active 2-benzofuran derivatives under copper- and ligand-free conditions. The catalyst performed superior catalytic performance compared with the analogous Pd/C and supported on other metal oxides under otherwise identical conditions. A broad set of aryl and alkyl terminal alkynes can be effectively coupled /cyclized with various o -iodophenols to afford their corresponding 2-benzofurans in good to high yields with good tolerance of multiple functional groups. Moreover, the catalyst showed good stability and could be reused several times without significant loss of activity.