Woodward cis-hydroxylation

The Woodward cis-hydroxylation is the chemical reaction of alkenes with iodine and silver acetate in wet acetic acid to form cis-diols. The reaction is named after its discoverer, Robert Burns Woodward.



This reaction has found application in steroid synthesis.

Reaction mechanism
The reaction of the iodine with the alkene is catalyzed by the silver acetate, thus forming an iodinium ion. The iodinium ion is opened via SN2 reaction by acetic acid (or silver acetate) to give the first intermediate, the iodo-acetate. Through anchimeric assistance, the iodine is displaced via another SN2 reaction to give the hydroxyl-acetate, which is subsequently hydrolyzed to the give the diol. The combination of two SN2 reactions is the key to forming the cis-diols. Note that only in ring-systems an actual cis isomer is formed.