A convenient synthesis of 3-aryl-δ-lactones

Various (±)-3-aryl-δ-lactones have been prepared from the corresponding arylacetic acids. The lithium dianion of the acid is alkylated with 1-bromo-3-chloropropane and the unpurified product is cyclized with DBU in typically ca. 80% yield over both steps. We have shown that lactones of this type can be converted to their corresponding 5,6-dihydropyan-2-ones and pyran-2-ones, which potentially provide useful sites for further functionalization of the lactone ring.