Ligand-free Pd/Ag-mediated dehydrogenative alkynylation of imidazole derivatives.

A variety of 2-alkynyl(benzo)imidazoles have been synthesized by dehydrogenative alkynylation of (benzo)imidazoles with terminal alkyne in NMP under air in the presence of Ag 2 CO 3 as the oxidant and Pd(OAc) 2 as the catalyst precursor. The data obtained in this study support a reaction mechanism involving a non-concerted metalation deprotonation (n-CMD) pathway.