Efficient synthesis of benzocyclohexanes via intramolecular Friedel–Crafts reaction of halogen free 6-acetoxy-4-alkenyl arenes

Benzocyclohexane derivatives were prepared highly stereoselectively by the cyclic Friedel–Crafts reaction of 6-acetoxy-4-alkenyl arenes in moderate to excellent yields in TFA/HOAc (3:1). It was observed that the rate of the cyclization as well as the yields of products depend largely on the substituents of the allylic acetate moiety.