The reaction of cycloalkene with
iodineâcerium(IV) ammonium nitrate (CAN) in
acetonitrileâwater (10:1â1:1) affords the
corresponding trans-iodohydrins and
trans-iodonitrates; when
iodineâcerium(IV) sulfate (CS) in
acetonitrileâwater (10:1) at 50 °C is used,
trans-iodohydrins are obtained preferentially.
The reaction mixtures of 5α-cholest-2-ene with iodine-ammonium cerium(IV) nitrate [CAN(IV)] were converted with potassium hydroxide in methanol-water to give the more hindered 2β,3β-diol in high yield. Cyclohexene and cycloheptene similarly reacted to the corresponding cis-diols in good yield. It was found that this reaction intermediate proceeds to give trans-iodoacetate via trans-iodonitrate. This new synthetic method provided several advantages over the Prevost reaction.