11/27/11 - Regioselective Formation of Enolates

   In molecules of biomedical importance it is necessary to gain a regioselective basis of enolate formation, which will eventually lead to the addition of an electrophilic substitution at that point.  I apologize for the lack of pictures to describe this reaction, but I would like for you to picture in your mind a cyclohexane with a carbonyl ketone at one of the points.  On this cyclohexanone there is a substituent at the beta position, which demands a regioselective method of adding to the alpha position.  The method required is the creation of the alpha-beta unsaturation of this cyclohexanone and then the additon of lithium metal (or any other cationic metal) into the solution along with ammonia and t-BuOH.  This mixture causes the release of an electron, which ends up radicalizing the beta position on the molecule which causes the protonation at this point from the alcohol added, and this pushes the unsaturation to make the enolate on the side of substitution.