Efficient Microwave-Assisted Synthesis of 9,9-Bis[4-(2-hydroxyethoxy)phenyl]fluorene from 9-Fluorenone and 2-Phenoxyethanol

Abstract 9‐Fluorenone (1) smoothly reacts with phenoxyethanol (2) in the presence of Al3+‐montmorillonite catalyst and 3‐mercaptopropionic acid as a cocatalyst under microwave irradiation at 160°C for 10 min to give 9,9‐bis[4‐(2‐hydroxyethoxy)phenyl]fluorene (3) in 81% yield, which was much higher than the yield of 33% obtained by conventional heating using an oil bath. A similar acceleration effect of microwave irradiation was observed in other metal‐cation‐exchanged montmorillonite catalysts as well.