Cobalt(II)-complex catalyzes efficiently the intramolecular C–N and C–O cross-couplings of Z-N′-(2-halophenyl)-N-phenylamidines and N-(2-bromophenyl)benzamides to afford the corresponding substituted benzimidazoles and benzoxazoles in the presence of K2CO3 at moderate temperature. The protocol is general, air stable and affords the products selectively in moderate to high yield.
钴(II)配合物有效催化Z - N '-(2-卤代苯基)-N-苯基am和N-(2-溴苯基)苯甲酰胺的分子内C – N和C – O交叉偶联,提供相应的取代苯并咪唑在中等温度下在K 2 CO 3存在下使用苯并恶唑和苯并恶唑。该方案是一般的,空气稳定的,并且以中等至高收率选择性地提供产物。
Copper-Catalyzed Intramolecular C−N Bond Formation: A Straightforward Synthesis of Benzimidazole Derivatives in Water
A straightforward, efficient, and more sustainable copper-catalyzed method has been developed for intramolecular N-arylation providing the benzimidazole ring system. With Cu2O (5 mol %) as the catalyst, DMEDA (10 mol %) as the ligand, and K2CO3 as the base, this protocol was applied to synthesize a small library of benzimidazoles in high yields. Remarkably, the reaction was exclusively carried out in water, rendering the methodology highly valuable from both environmental and economical points of view.