Gas-Phase Nazarov Cyclization of Protonated 2-Methoxy and 2-Hydroxychalcone: An Example of Intramolecular Proton-Transport Catalysis

Protonated 2-methoxy and 2-hydroxychalcones lose ketene through intermediate protonated 3-arylindanones, a rearrangement driven by proton-transfer catalysis.