Acceptorless Dehydrogenative Annulation of Dihydroxybenzophenones to Hydroxyxanthones by a CeO2-Supported Pd Catalyst

Abstract Hydroxyxanthones have attracted increasing attention because they often exhibit diverse pharmacological activities depending on their substituents. Herein, we report the acceptorless dehydrogenative annulation of dihydroxybenzophenones to afford hydroxyxanthones using a CeO2-supported Pd catalyst without any additives. The present dehydrogenative annulation is likely promoted by Pd ensembles of Pd nanoparticles, with one of the hydroxy groups in dihydroxybenzophenones serving as a directing group.