Aminoguanidine-Catalyzed Reductive Cyclization of o-Phenylenediamines with CO2 in the Presence of Triethoxysilane

An inexpensive and efficient aminoguanidinecatalyzed reductive cyclization of o-phenylenediamines with CO2 in the presence of triethoxysilane is described. Various functionalized benzimidazoles, benzoxazole, and benzothiazole were synthesized in high yields. Mechanistic studies indicate that formic acid as a cocatalyst promotes the cyclization reaction.

Automated summary

An inexpensive and efficient method for the synthesis of various functionalized benzimidazoles, benzoxazole, and benzothiazole through a CO2-mediated reductive cyclization reaction in the presence of triethoxysilane is described. Mechanistic studies reveal that formic acid acts as a cocatalyst to promote the cyclization reaction.