The Mannich reaction is a carbon–carbon bond-forming reaction that involves the condensation of an aldehyde or ketone with a tertiary amine or an amine salt and a compound containing an active hydrogen atom (like a phenol, enol, or another carbonyl compound) in the presence of an acid catalyst. The product of a Mannich reaction is a β-amino carbonyl compound, which is a versatile intermediate that can be used to synthesize a wide variety of chemical compounds such as natural products, pharmaceuticals, and polymers.
This reaction is useful in organic synthesis because it allows the direct addition of an aminomethyl group to a carbonyl, effectively constructing a new carbon-nitrogen bond. As such, the Mannich reaction is valuable for building complex molecules with β-amino carbonyl functionality, which are prevalent in various biologically active compounds.