Abstract The cleavage reaction of ethereal and thioethereal bonds with sodium iodide and acyl chloride has been studied. In all the 1, 3-benzodioxoles and-benzoxathioles studied, the opening of the heterocyclic ring with formation of 1, 2-diacetoxybenzene or 2- hydroxythiophenol diacetic ester and gem-diiodoalkanes and iodoalkenes has been observed. The structure of newly prepared compounds has been determined by analytical ...