Benzotriazolium Salts: Emergent Readily Accessible Bench-Stable Lewis Acid Catalysts.

In this work, benzotriazolium salts have been introduced as efficient, readily accessible, bench-stable Lewis acid catalysts. Though these sorts of N-heterocyclic compounds have found wide applications as ionic liquids or electrolytes, their Lewis acid catalytic activity remained unexplored. Herein, their potential as Lewis acid catalysts was demonstrated in two prototypical allylic and Nazarov cyclization reactions, showing a matching reactivity and allowing low catalytic loadings (down to 0.5 mol %).