Superacid-catalyzed Friedel–Crafts cyclization of unactivated alkenes

Trifluoromethanesulfonimide is an effective catalyst for Friedel–Crafts cyclizations of simple, nonpolarized alkenes with a variety of pendant arenes. A catalyst loading of 0.5 – 1.0 mol % effects clean cyclization to form 5- to 7-membered carbocycles with generally short reaction times and good to excellent yields under reflux or microwave heating.