Examples of Enamine Reactions

As noted, N-alkylation of enamines is common for aldehydes and some ketones. Michael addition reactions avoid this problem thanks to their reversibility. The third example shows such a reaction, and the "Toggle Mechanism" button displays a possible mechanism. The C-alkylation intermediate is thermodynamically more stable than the N-alkylation species, so it predominates at equilibrium. Both the charges in this intermediate are stabilized by delocalization, and hydrolysis rapidly converts it to the aldehyde-ester product. An interesting alternative is ring closure to a neutral enol ether compound (shown in the blue shaded box) which would also be hydrolyzed to the same product.