Chemoenzymatic selective formation of C–N bonds in a benzimidazole heterocycle†
A novel and efficient method for the chemoenzymatic selective formation of C–N bonds in the synthesis of a 2-substituted benzimidazole heterocycle, catalyzed by lipase from porcine pancreas (PPL), has been developed. A series of 2-substituted benzimidazole derivatives were synthesized under mild conditions, with high yields (89–96%) and high selectivity. The blank and control experiments reveal that PPL plays an important catalytic role during the selective C–N bond formation process. The results demonstrate that PPL has a broad catalytic tolerance towards different aldehydes containing electron-donating or -withdrawing groups in this reaction. This study provides an efficient tool for the selective formation of C–N bonds in the synthesis of 2-substituted benzimidazole derivatives.