In the Strecker synthesis, an aldehyde and a nitrile react to yield an amino acid.

The aldehyde typically employed in the Strecker synthesis is either formaldehyde or a related aldehyde derivative, such as benzaldehyde. The nitrile commonly used is potassium cyanide ($\text{KCN}$), although other nitriles can also be utilized. These reagents are combined with ammonia in the presence of an acid catalyst, commonly hydrochloric acid ($\text{HCl}$), to produce the target amino acid.

The reaction occurs through a sequence of steps, starting with the formation of an imine intermediate between the aldehyde and ammonia. Subsequently, this imine reacts with the nitrile, leading to the formation of an alpha-amino nitrile. This intermediate is then hydrolyzed to generate the desired amino acid.

The Strecker synthesis is a valuable method for producing amino acids, which are crucial building blocks of proteins. This synthesis is also employed in the manufacture of pharmaceuticals and various organic compounds. However, the use of cyanide in this reaction poses significant hazards, necessitating careful handling and disposal practices. As a safer alternative, methods such as the Gabriel synthesis have been developed to eliminate the need for cyanide.