Aerobic oxidation of alkenes to esters of vicinal diols with a syn-configuration catalyzed by I2 and the H5PV2Mo10O40 polyoxometalate

A new method for the synthesis of vicinal diols from alkenes has been developed. Reaction Of Molecular iodine in the presence of a polyoxometalate as oxidation Catalyst under aerobic conditions in acetic acid solvent leads to the oxidative iodoacetoxylation of: an alkene, i.e. formation of a 1,2-iodoacetate. Further in situ Substitution of the iodide by water yields the 1,2-diol monoacetate with a predominantly (ca. 4.5: 1) cis-configuration. Further esterification under the reaction's acidic conditions leads also to the cis-diacetate. The method may be Valuable for the synthesis of cis-vicinal diols Without use of toxic osmium catalysts.