[[Ficheiro:Ascorbic acidity3.png|thumb|center|upright=2.8|Movemento de pares de electróns na desprotonación do [[ácido ascórbico]] ([[vitamina C]]), convertindo un enediol (esquerda) nun enolato (dereita).]]
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=== Desprotonación selectiva na formación de enolatos ===
nas cetonas con hidróxenos α en ambos os lados do carbono do carbonilo, selectivity of deprotonation may be achieved to generate two different enolate structures. At low temperatures (-78°C, i.e. dry ice bath), in aprotic solvents, and with bulky non-equilibrating bases (e.g. [[lithium diisopropylamide|LDA]]) the "kinetic" proton may be removed. The "kinetic" proton is the one which is [[steric effects|sterically]] most accessible. Under thermodynamic conditions (higher temperatures, weak base, and protic solvent) equilibrium is established between the ketone and the two possible enolates, the enolate favoured is termed the "thermodynamic" enolate and is favoured because of its lower energy level than the other possible enolate.{{clarify|date=October 2010}}<!-- is thermodynamic always the non-kinetic one? if so, explain what about the "more hindered" nature makes it more stable; if only sometimes, don't leave impression that these are clear opposite regiochemical results --> Thus, by choosing the optimal conditions to generate an enolate, one can increase the yield of the desired product while minimizing formation of undesired products.
