Enamines are labile and therefore chemically useful moieties which can be easily produced from commercially available starting reagents. A common route for enamine production is via an acid-catalyzed nucleophilic reaction of ketone or aldehyde species containing an α-hydrogen with secondary amines.  Acid catalysis is not always required, if the pK of the reacting amine is sufficiently high (for example, pyrrolidine, which has a pK of 11.26). If the pK of the reacting amine is low, however, then acid catalysis is required through both the addition and the dehydration steps (common dehydrating agents include MgSO and NaSO). Primary amines are usually not used for enamine synthesis due to the preferential formation of the more thermodynamically stable imine species. Methyl ketone self-condensation is a side-reaction which can be avoided through the addition of TiCl into the reaction mixture (to act as a water scavenger). An example of an aldehyde reacting with a secondary amine to form an enamine via a carbinolamine intermediate is shown below: