Mild and Highly Efficient Method for Synthesis of 14-Aryl(alkyl)-14H-dibenzo[a,j]xanthenes and 1,8-Dioxooctahydroxanthene Derivatives Using Pentafluorophenyl Ammonium Triflate as a Novel Organocatalyst

A simple and facile synthesis of 14-aryl and alkyl-14H-dibenzo[a,j]xanthenes and 1,8-dioxooctahydroxanthene derivatives has been successfully developed by treatment of β-naphthol or dimedone with aldehydes under mild conditions in the presence of a pentafluorophenyl ammonium triflate (PFPAT) organocatalyst. These catalytic condensation reactions represent green chemical processes and the PFPAT organocatalyst is air-stable, cost-effective, easy to handle, and easily removed from the reaction mixtures. The advantages of this method are many, including a high yield, clean and mild reaction conditions, high atom-economy, short reaction time, low environmental impact, wide substrate scope, and excellent product purity.