Ring Rearrangement Reactions of 4‐Alkenylisocoumarins and Photophysical Evaluation of Multi‐Substituted Anthracene Products

Abstract

AbstractHerein we report that readily available 4‐alkenylisocoumarins can be regarded as potent dienolate equivalents. For example, lactol silyl ethers derived from 4‐alkenylisocoumarins were selectively converted to the corresponding benzo‐homophthalates through a fluoride‐induced ring opening step that was followed by a ring closure through a vinylogous intramolecular aldol condensation. Likewise, nucleophilic activation of 4‐alkenylisocoumarins directly yields diversely poly‐substituted naphthalenes and anthracenes without formation of any regioisomer. Photophysical evaluation of a set of thus obtained 1,3‐di‐ and 1,3,4‐trisubstituted anthracenes reveals their distinct intramolecular charge transfer (ICT) character during light absorption in polar solutions and excimer emission from the solid state when a face‐to‐face π‐stacked molecular assembly is present in the crystal packing.