Regiospecific Synthesis of N-Alkyl-benzimidazoles from o-Haloanilines

Significance

Benzimidazoles find a broad range of applications in material science, as well as biologically active compounds. They are sometimes difficult to prepare in regioisomerically pure form. This method uses available 2-haloanilines and primary amides as starting materials. It is a combination of the Cu(I)-catalyzed amidation with the subsequent ring closure, affording products with complete regioselectivity. This method is more economical and substantially less sensitive to the substitution pattern than similar Pd-catalyzed processes.