Tf2NH‐Mediated Twofold Aromatization Reaction of Dimers of Ethynylcyclopropanes to Bibenzoisocoumarins

Abstract Tf 2 NH‐mediated twofold aromatization reaction of dimeric ethynyl‐substituted cyclopropanes followed by lactonization has been developed for facile synthesis of bibenzo[ f ]isocourmarin derivatives in moderate to good yields. In particular, with respect to the electron‐rich phenyl ring for intramolecular hydroarylation with alkynes, a single or double direct ring‐opening aromatization reaction occurred to produce the isomeric benzo[ h ]isocoumarin moiety. Preliminary photophysical properties of these bibenzoisocoumarin isomers are provided as well.