Friedel–Crafts cyclization of tertiary alcohols using bismuth(III) triflate

Bismuth(III) triflate [Bi(OTf)3] has been developed as an efficient and mild catalyst for intramolecular Friedel–Crafts cyclizations of tertiary alcohols to prepare disubstituted tetrahydronapthalenes, chromans, thiochromans, tetrahydroquinolines, and tetrahydroiso-quinolines. The method represents a unified strategy to synthesize a variety of ring systems from tertiary alcohols using a common Lewis acid.