Gold(I)-catalyzed tandem cyclization of cyclopropylidene-tethered propargylic alcohols: an approach to functionalized naphtho[2,3-c]pyrans

An unprecedented gold(I)-catalyzed cyclization of cyclopropylidene-tethered propargylic alcohols via a 6-endo-dig enyne cyclization followed by a ring-opening of cyclopropane and nucleophilic closure reaction to construct naphtho[2,3-c]pyrans was developed. This transformation represents a highly efficient method for the synthesis of polycyclic compounds in one-pot, and two new rings are formed in an atom economic manner.