Retro-Friedel-Crafts-Type Acidic Ring-Opening of Triptycenes: A New Synthetic Approach to Acenes

Chemistry. 2022 Feb 24;28(12):e202104160. doi: 10.1002/chem.202104160. Epub 2022 Feb 3.

Abstract

The triptycene scaffold has been ring-opened by using a retro-Friedel-Crafts-type reaction under acidic conditions to give its corresponding anthrone product. 9-Hydroxytriptycenes and unsubstituted triptycene undergo ring-opening reaction under strongly acidic conditions, such as with TfOH. An investigation of the substitution effect has revealed that the electron-donating group on the arene moiety allows the reaction to proceed in the presence of a weaker acid, such as TFA. In addition, the reaction has been successfully applied toward the synthesis of tetracene.

Keywords: acenes; anthrones; retro-Friedel-Crafts reaction; ring-opening reaction; triptycenes.