Oxidant-Switchable Selective Synthesis of 2-Aminobenzimidazoles via C–H Amination/Acetoxylation of Guanidines
摘要:
The iodine(III) compound promoted CH amination and tandem CH amination/acetoxylation of guanidines are achieved for the first time to provide efficiently 2-aminobenzimidazoles and acetoxyl-substituted 2-aminobenzimidazoles, respectively. The amount and type of iodine(III) compounds control the selective syntheses of two types of 2-aminobenzimidazoles. This reaction shows good regioselectivity when unsymmetrical substrates are used.
three-component reaction of cyanamides, amines, and diaryliodonium triflates was developed for the synthesis of guanidines. The mild reaction accommodates both aromatic and aliphatic amines and provides the products in good yields with good functional group tolerance. Moreover, it was demonstrated that C–H activation of the arenes could be realized for the direct preparation of guanidines.