Glycol cleavage 4102521 164949827 2007-10-16T13:50:50Z Edgar181 491706 removed extra content specific to [[glycol]]s; rewrote to correct and clarify; reaction diagram added '''Glycol cleavage''' is a specific type of organic chemistry [[oxidation]]. The carbon-carbon bond in a ([[vicinal (chemistry)|vicinal]] [[diol]] (glycol) is cleaved and replaced with two carbon-oxygen double bonds. Depending on the substitution pattern in the diol, either [[ketone]]s or [[aldehyde]]s may be formed. Glycol cleavage is an important reaction in the laboratory because it is useful for determining the structures of sugars. After cleavage takes place the ketone and aldehyde fragments can be inspected and the location of the former hydroxyl groups ascertained. ==Reagents== [[Periodic acid]] (HIO<sub>4</sub>) and [[lead(IV) acetate|lead tetraacetate]] (Pb(OAc)<sub>4</sub>) are the most common reagents used for glycol cleavage. These reactions involve cyclic [[reactive intermediate|intermediates]] which then decompose to form ketones (if the [[side chain|R groups]] are not H) or aldehydes (if one of the R groups is H). :[[Image:Glycol cleavage.png|thumb|left|500px|Glycol cleavage with Pb(OAc)<sub>4</sub> involves a cyclic intermediate.]]<br style="clear:both;"/> Warm concentrated [[potassium permanganate]] (KMnO<sub>4</sub>) will react with an alkene to form a glycol and will then immediately cleave the glycol to give stable ketones or oxidizable aldehydes. The aldehydes will react further to become [[carboxylic acid]]s. Controlling the temperature and concentration of the reagent can keep the reaction from continuing past the formation of the glycol. ==References== *Wade, L. G. ''Organic Chemistry'', 6th ed.., Prentice Hall, Upper Saddle River, New Jersey, 2005; pp 358-361, pp 489-490. ISBN 0131478826 ==External links== *[http://www.cem.msu.edu/~reusch/VirtualText/addene2.htm#add4e www.cem.msu.edu] [[Category:Organic redox reactions]]