Closing the Loop in Brønsted Acid Catalysis: Anti-Corrosive, Self-Micellizing, and Completely Recyclable Phytic Acid Aqueous System for N-Allylation of Carbazoles

Phytic acid (PA), the most abundant inositol phosphate in plants and a material currently classified as agricultural waste, is a naturally occurring Brønsted acid with unique properties. This study presents an innovative and eco-friendly strategy for N-allylation of carbazoles using PA as a nontoxic, highly reusable, and anticorrosive Brønsted acid catalyst in aqueous media, achieving up to 94% isolated yield and exceptional selectivity for N-allylcarbazoles. In this transformation, PA not only serves as a Brønsted acid catalyst but also promotes substrate dispersion in aqueous systems through micelle formation. Moreover, the system exhibits excellent anticorrosive performance for carbon steel compared to conventional Brønsted acids. Notably, the PA-aqueous catalytic system demonstrates remarkable recyclability and could undergo at least 16 cycles without any activity or selectivity loss in current catalysis. This multifunctional PA aqueous system has great potential for advancing diverse Brønsted acid-catalyzed reactions toward greener and lower-cost industrial processes.