Novel phosphoryloxylactonisation of pentenoic acids mediated by ammonium iodide

Using ammonium iodide as a catalyst and m-chloroperbenzoic acid as the oxidant, a novel and efficient procedure has been developed for phosphoryloxylactonisation of alkenoic acids in CH3CN at room temperature, which provides the corresponding phosphoryloxylactones in good yields. In this protocol, it is proposed that ammonium iodide catalyst is first oxidised to hypoiodous acid, which reacts with the alkenoic acid to afford the corresponding iodolactone. Then, the iodolactone is further transformed into a hypervalent iodine intermediate by continuing oxidation, and finally the in situ generated active iodine species reacts with a diaryl phosphate to furnish the phosphoryloxylactone end product.