Herein, a simple and practical method for generating isoacenofuran, a new π-extended quinoidal building block, was developed. A three-step protocol involving double nucleophilic addns. of alkynyllithiums to acene-2,3-dicarbaldehyde, mono-oxidn., and acid-promoted cyclization enables the generation of the target mol., which is trapped by a dienophile to produce highly condensed acenequinones [e.g., treatment of I (derived from the dialdehyde) with TFA in presence of naphthoquinone as trapping agent for the intermediate isoacenofuran afforded endo/exo-II (86%)]. Further transformations by double nucleophilic addns. of alkynyllithium to hexacenequinone, followed by reductive aromatization, produce tetraalkynylhexacenes with a remarkably higher stability than that of the previously reported substituted hexacenes. [on SciFinder(R)]
各種検索
サポート
ヘルプ