Monoprotection of Arylene‐Diacetic Acids Allowing the Build‐Up of Longer Aromatic Ribbons by Successive Perkin Condensations

Aryl diacetic mono‐acid mono‐esters were designed and efficiently synthesized as mono‐protected bifunctional building blocks for the Perkin condensation between arylacetic acids and arylglyoxylic acids. Although, so far, this Perkin strategy has only been used for the formation of linear trimers or macrocyclic tetramers, it can now be adapted to the formation of pentameric conjugated species to give access, after adequate intramolecular cyclizations, to longer and more complex carboxy‐substituted polycyclic aromatic compounds. Monoprotection of arylene‐diacetic acids allows the formation of flexible five‐block precursors by multiple Perkin reactions. Final graphitization of these precursors leads to elongated octasubstituted polycyclic arenes, such as a [14]phenacene octaester.