Transition-Metal-Free/ Boric Acid Catalysed Mechanochemical Synthesis of Symmetrical and Unsymmetrical Azobenzenes: A Sustainable Approach

Abstract

ABSTRACT: A mechanochemical protocol employing boric acid, an economical and environmentally benign inorganic acid catalyst, enables the synthesis of symmetric and unsymmetric azobenzenes from diverse amines. This grinding-based, solvent-free mechanochemical approach provides a sustainable alternative to conventional methods, avoiding harsh transition-metal catalysts. The use of oxone as a green oxidant, operation under ambient conditions, simplified work-up, and overall environmental compatibility highlights the advantages of this methodology.