Application of IBX Method for the Synthesis of Ketones from Carboxylic Acids

One of the most common reactions in chemistry is the synthesis of ketones from acids1−4. First, the acid is changed into its chloride. Then the acid chloride reacts with an organometallic reagent or gives a FriedelCrafts type reaction in the presence of Lewis acids. These methods are very useful for most aliphatic acid halides and good yields can be obtained in this way. However, if this method is used for propionic acid, which contains the methoxy phenyl group, very low yields of ketones (5-12%) are obtained. Attempts at increasing the yields of ketones also failed using the Corey-House method. These attempts led either to the formation of polymeric material and intractable tar as reaction products or to intermolecular cyclisation reactions, which were isolated after the reaction. In this study, the critical point in the classical method is the halogenation of the acids. After the acid halide is obtained, other molecules either react with this acid halide or can cause intermolecular cyclisation reactions due to the high reactivity of the methoxy phenyl group on the molecule. For this reason, obtaining and controlling the acid chloride formation is very difficult. Furthermore, further reactions with the obtained small amount of acid chloride, using Grignard reagent, are very difficult under normal conditions. Additionally, the alkylation reaction of this type of acid chloride with Grignard reagent always provides dialkylation products instead of mono alkylation ones because reducing the reaction temperature ∗Corresponding author