Sustainable production of triazoles from lignin major motifs

Abstract

AbstractAn efficiently catalyzed synthesis of pharmaceutically relevant 1,2,3‐trazoles from renewable resources is highly desirable. However, due to incompatible catalysis conditions, this endeavor remained challenging so far. Herein, a practical access protocol to 1,2,3‐triazoles, starting from lignin phenolic β‐O‐4 with γ‐OH group utilizing a vanadium‐based catalyst is presented. A broad substrate scope reaching up to 97 % yield of 1,2,3‐triazoles are obtained. The reaction pathway includes selective cleavage of double C−O bonds, cycloaddition, and dehydrogenation. Mechanistic studies and density‐functional theory (DFT) calculations suggest that the V‐based complex acts as a bifunctional catalyst for both selective C−O bonds cleavage and dehydrogenation. This synthetic pathway has been applied for the synthesis of pharmacological and biological active carbohydrate derivatives starting from biomass components as feedstock, enabling a potential sustainable route to triazolyl carbohydrate derivatives, which paves the way for lignin‐based heterocyclic aromatics in the pharmaceutical applications.