A Three-Step Process To Facilitate the Annulation of Polycyclic Aromatic Hydrocarbons

Abstract

A new efficient three-step process to annulate polycyclic aromatic hydrocarbons (PAHs) has been developed, providing access to PAHs with saturated rings that under current chemical methods would be difficult to produce in an efficient manner. This method relies on a palladium-catalyzed cross-coupling reaction of various brominated PAHs with cyclohexanone to yield α-arylated ketones, which are converted to regiospecific vinyl triflates and cyclized by a palladium-catalyzed intramolecular arene-vinyl triflate coupling to produce PAHs with incorporated saturated rings or "tetrahydroindeno-annulated" PAHs.

Three-Step Synthesis of Fluoranthenes through Pd-Catalyzed Inter- and Intramolecular C–H Arylation

“…The second step is nonaflation of the hydroxy group through introduction of a nonafluorobutanesulfonyl (Nf) group, which is more resistant to O–SO 2 cleavage than the commonly used trifluoromethanesulfonyl group. , In addition, the nonaflating agent, NfF, is generally cheaper than the common triflating agent, Tf 2 O. The third step is the Pd-catalyzed intramolecular C–H arylation of the corresponding nonaflates. − This step was designed based on the seminal work of fluoranthene synthesis by Rice and Cai . Herein, we demonstrate the feasibility of this synthetic scheme, which provides a useful method for fluoranthene synthesis.…”