The p-toluenesulfonates of 2-substituted 1, 3-diogane-5-of with 2-substitnents being hydrogen, isopropyl, phenyl, and grnitrophenyl and of 1, 3-di-O-alkylglycerol with alkyls as methyl, ethyl, isopropyl, and benzyl groups are subject to the reaction with sodium iodide in boiling butanone. It is found that the cyclic sulfonates do not react, but the linear esters undergo slow ezohange to form the corresponding iodides.