Fast and efficient synthesis of flavanones from cinnamic acids

Abstract

ABSTRACTA fast and efficient synthesis of flavanones from cinnamic acids in three steps has been developed. First, the cinnamic acid was converted to cinnamyol chlorides using SOCl2. The acid chlorides were then treated with substituted phenols in BF3 · OEt2 to furnish corresponding chalcones in 42(75% yields. Base-catalyzed cyclization of the chalcones at room temperature afforded corresponding flavones in 85–95% yields. The conversion of the cinnamic acid derivatives to corresponding chalcones was found to be sensitive to the position and nature of the substituents on the aromatic rings.