A concise synthesis of polyhydroxydihydrochalcones and homoisoflavonoids

A general and single step synthesis of polyhydroxydihydrochalcones from the readily available phenols and dihydrocinnamic acids using BF3·Et2O is described. The method allows the synthesis of a wide range of compounds with multiple phenolic hydroxyls and other substituents. These dihydrochalcones are converted into homoisoflavonoids by DMF/PCl5 and the methodology has been applied to the synthesis of naturally occurring phloretin and 5,7-dihydroxy-3-[(4-hydroxyphenyl)methyl]-4H-chromen-4-one. The antioxidant activity of dihydrochalcones and homoisoflavonoids was determined by superoxide free radical (NBT) and DPPH free radical scavenging methods. Polyhydroxydihydrochalcones , , and homoisoflavonoids , , displayed excellent antioxidant activity.