The reaction of cycloalkene with iodine-cerium(iv) ammonium nitrate (C
AN) in acetonitrile-water (10:1-1:1) affords the corresponding trans-i
odohydrins and trans-iodonitrates; when iodine-cerium(iv) sulfate (CS)
in acetonitrile-water (10:1) at 50 degrees C is used, trans-iodohydri
ns are obtained preferentially.