benzoate to produce trans-diols; the Woodward modification of the Prévost reaction uses silver acetate to produce cis-diols. In both the Prévost and Woodward reactions, iodine is first added to the alkene producing a cyclic iodinium ion. The anion from the corresponding silver salt is then added by nucleophilic substitution to the iodinium ion. In the Prévost reaction, the iodinium ion undergoes nucleophilic attack by benzoate anion. The benzoate anion acts as a nucleophile again to displace iodide through a neighboring-group participation mechanism. A second benzoate anion reacts with the intermediate to produce the anti-substituted dibenzoate product, which can then undergo hydrolysis to yield trans-diols. The Woodward modification of the Prévost reaction yields cis-diols. Acetate anion reacts with the cyclic iodinium ion to yield an oxonium ion intermediate. This can then readily react with water to give the monoacetate, which can then be hydrolyzed to give a cis-diol To eliminate the need for silver salts, Sudalai and coworkers modified the Prévost-Woodward reaction; the reaction is catalyzed with LiBr, and uses NaIO4 and PhI(OAc)2 as oxidants. LiBr reacts with NaIO4 and acetic acid to produce lithium acetate, which can then proceed through the reaction as previously mentioned. The protocol produced high dr for the corresponding diol, depending on the oxidant chosen. Applications The synthesis of highly substituted and stereospecific sugars is important since polysaccharides make up a large class of compounds found in nature. One specific example is in the biologically active molecule kakelokelose, which has been shown to have anti-HIV activity. Research conducted by Harris et al. have worked on an enantiospecific synthesis of sugars pertaining to kakelokelose and other sugars, employing many different dihydroxylation reactions with osmium catalyst. Vinylfuran was reacted under Sharpless conditions with AD-mix-α to yield (R)-diol. Later, a resulting dihydropyran was reacted under Upjohn conditions to yield the resulting sugar, mannose (where R represents either H or a protecting group). Additionally, talose and gulose were also synthesized from a different dihydropyran. Since the compound contains an allylic alcohol, Upjohn conditions and the Upjohn modification using TMEDA as the secondary oxidant to create the resulting sugars (where R represents either H or a protecting group). Another application of dihydroxylation methods is in the synthesis of steroids. Brassinosteroids are a class of steroids shown to regulate plant growth and has been shown to have agricultural activity as an insecticide. This class of steroids contains the standard framework of steroids