An effective method for the preparation of chlorolactones

The effective chlorolactonization of alkenoic acids with (diacetoxyiodo)benzene and lithium chloride under mild conditions have been studied. Experiments show that various 4-pentenoic acids react with (diacetoxyiodo)benzene and lithium chloride fluently in CH3OH at room temperature, obtaining five-membered chlorolactones in good yields in short times. Other alkenoic acids, such as 3-butenoic acid and trans 3-hexenoic acid give some more complicated results, and 4-pentynoic acid provides a chloroenol lactone with Z configuration in 40% of yield.