Aluminum Triflate Catalyzed Tandem Reactions of d‑Galactal: Toward Chiral Benzopyrans, Chromenes, and Chromans

3,4,6-Tri-<i>O</i>-acetyl-d-galactal is selectively converted into 1-<i>O</i>-aryl-2-deoxy derivatives or chiral bridged benzopyrans under Al­(OTf)₃ catalysis, depending on reaction conditions. The benzopyrans react with Al­(OTf)₃/acetic anhydride in ring-opening reactions in the absence or presence of acetic acid to selectively produce chiral chromenes or chromans, respectively, in high yields