Intermolecular Oxidative Friedel-Crafts Reaction Triggered Ring Expansion Affording 9,10-Diarylphenanthrenes.
Lu YangIlya D GridnevMasahiro TeradaTienan JinPublished in: Organic letters (2020)
A novel intermolecular tandem oxidative aromatic coupling between arylidene fluorenes and unfunctionalized aromatics mediated by a DDQ/TFA oxidation system has been developed for the construction of 9,10-diarylphenanthrenes (DAPs). The formation of a benzylic carbocation species possessing a quaternary sp3-carbon center on the fluorene moiety by an intermolecular oxidative Friedel-Crafts reaction of two different arenes successfully triggered the subsequent ring expansion to afford DAPs.