Iron-catalyzed synthesis of phenanthrenes via intramolecular hydroarylation of arene-alkynes

An Fe(OTf)3-catalyzed intramolecular hydroarylation of arene-alkynes with high functional group tolerance has been reported, affording a series of phenanthrene derivatives efficiently. A low catalytic amount of Fe(OTf)3 is applied in this reaction. This transformation provides a convenient and practical method for the preparation of phenanthrenes.