Cu-Catalyzed Heterannulation Route to Benzimidazoles from ortho-Haloacetanilides

Significance

An efficient synthetic method for benzimidazoles involving the sequential coupling of o-haloacetanilide derivatives with amidines, hydrolysis of the amide intermediates and intramolecular cyclization is reported. The products were further N-arylated, with the whole process being conducted in one pot. The yields range from mediocre to good, both for the first step and for the whole two-step process. Bromo- and iodoanilides both participate in the reaction but the reaction with chlorides was not reported. The reaction was extensively optimized and the substitution pattern on haloanilide or amidine reaction partners was moderately studied. Some of the intermediates along the proposed reaction pathway were identified by ESI-MS.