The Strecker amino acid synthesis, devised by Adolph Strecker, is a series of chemical reactions that synthesize an amino acid from an aldehyde (or ketone).^[1][2] The aldehyde is condensed with ammonium chloride in the presence of potassium cyanide to form an α-aminonitrile, which is subsequently hydrolyzed to give the desired amino-acid. ^{[3] [4]}

While usage of ammonium salts gives unsubstituted amino acids, primary and secondary amines also successfully give substituted amino acids. Likewise, the usage of ketones, instead of aldehydes, gives α,α-disubstituted amino acids. ^[5]

The traditional synthesis of Adolph Strecker from 1850 gives racemic α-amino nitriles, but recently several procedures utilizing asymmetric auxiliaries ^[6] or asymmetric catalysts ^{[7] [8]} have been developed. ^[9]

Contents 1 Reaction mechanism 2 Scope 3 References 4 See also

[edit] Reaction mechanism

The reaction mechanism for this reaction is sketched below. In part one aldehyde 1.1 reacts with ammonia in a nucleophilic addition to the hemiaminal 1.3 which attracts a proton to form iminium ion 1.5 by elimination of water. A second nucleophilic addition of the cyanide ion forms the aminonitrile 1.6.

Strecker synthesis part I		Strecker synthesis part II

In stage two a proton activates aminonitrile 2.1 for nucleophilic addition of two equivalents of water to intermediate 2.6 which eliminates ammonia and a proton to final product 2.7.

[edit] Scope

An example of present-day use of the Strecker synthesis is a multikilogram scale synthesis of a valine derivative starting from 3-methyl-2-butanone ^{[10] [11]}:

[edit] References

[edit] See also

• Bucherer-Bergs reaction