Benzylation of 1,3-Dicarbonyl Compounds with Benzyl Alcohols Promoted by Perfluorosulfonic Acid Resin

The catalytic performance of Perfluorosulfonic acid resin (PFSA), a solid superacid, was studied in the catalytic benzylation of 1,3-dicarbonyl compounds with benzylic alcohols. The PFSA-catalyzed reactions could proceed smoothly to provide the products under solvent-free conditions or in toluene and dichloromethane, which gave moderate to excellent yields. Due to its high chemical stability, PFSA was quite stable under the reaction conditions and could be recovered at least eight times without significant reduction of its catalytic effect. Moreover, this reaction was investigated at a 20 mmol scale, which indicated the potential applicability of the large-scale industrial synthesis. Finally, the mechanism of the PFSA-catalyzed benzylation of 1,3-dicarbonyl compounds with benzylic alcohols was also investigated. Perfluorosulfonic acid resin has been applied for the first time as a highly effective and general catalyst for the benzylation of 1,3-dicarbonyl compounds with benzylic alcohols and alkenes. The PFSA-catalyzed reactions could proceed smoothly to provide the products under solvent-free conditions, which gave moderate to excellent yields with water as the sole byproduct.image