When is a reaction said to be under kinetic control, is it not easily reversible?
A product formed under kinetic conditions may or not be reversible under the conditions of the reaction. Here is an example of one that is reversible under the reaction conditions. Kinetic control is determined by the difference in activation energy (&Delta;Ea) of the two pathways. The thermodynamic equilibrium is determined by &Delta;&Delta;Go. Acetoacetic ester (AAE 1) is a mixture of keto and enol forms. Bromination of AAE in an inert solvent rapidly gives &alpha;-bromoAAE 2 in addition to HBr. This is the product that is formed faster having a lower activation energy. This reaction is also  reversible, initiated by HBr (microscopic reversibility). Eventually, the more stable &gamma;-bromoAAE 3 is formed from AAE 1 by enolization toward C4 (&gamma;-position) of AAE under the influence of HBr.