Boron sulfonic acid (BSA) catalyzed selective synthesis of aryl-bis(2-hydroxynaphth-1-yl)methanes and 14-alkyl- and 14-aryl-14H-dibenzoxanthenes under solvent-free condition

This study investigated the selective synthesis of aryl-bis(2-hydroxy-1-naphthyl)methane for the first time under microwave irradiation in solvent-free medium within 5 min using 10 mol % of B(HSO4)3 (BSA) as reusable solid acid catalyst. The same reaction could also be conducted at 90-100 °C in neat for the formation of alkyl or aryl 14H-dibenzoxanthenes in presence of BSA catalyst with excellent yields.