Metal‐Free Three‐Component Assembly of Fully Substituted 1,2,3‐Triazoles

Abstract A practical domino three‐component protocol involving aldehydes, amines, and α‐diazo‐β‐ketosulfones provides efficient access to fully substituted 1,2,3‐triazoles. The process proceeds through a tandem Schiff‐base formation and 1,3‐dipolar cycloaddition to generate a key sulfonyltriazoline intermediate, which subsequently undergoes an oxidative aromatization with the aid of air or iodine. The three‐component protocol obviates the need of expensive metal catalysts, proceeds under mildly basic conditions, and tolerates a wide range of synthetically useful (hetero)aryl and aliphatic aldehydes, and functionalized amines.