We have synthesized a series of 8-acetylpsoralens in which methyl and hydrogen substitutions were systematically varied at the 4-and 5'-positions. Claisen rearrangement was employed in developing the furano ring, and acetyl migration during the rearrangement was identified as a major side reaction. This migration was circumvented by applying a diethylaluminum chloride catalyzed Claisen rearrangement to the pyrone ring-opened ...