Cyanoethylation

Cyanoethylation is a process for the attachment of CH₂CH₂CN group to another organic substrate. The method is used in the synthesis of organic compounds.[1]

Cyanoethylation entails addition of protic nucleophiles to acrylonitrile. Typical protic nucleophiles are alcohols, thiols, and amines. Two new bonds form: C-H and C-X (X = carbon, nitrogen, sulfur, phosphorus, etc):

${\displaystyle \mathrm {YH+H_{2}C{=}CH{-}CN\longrightarrow Y{-}CH_{2}{-}CH_{2}{-}CN} }$

The β-carbon atom that is furthest from the nitrile group is positively polarized and therefore binds the heteroatom on the nucleophile. Acrylonitrile is a Michael acceptor.[2] The reaction is normally catalyzed by a base.[3]

Tris(cyanoethyl)phosphine is produced by the cyanoethylation of phosphine.[4]

Cyanethylation is used to prepared numerous commercial chemicals. Detailed laboratory procedures are available for several variants of this reaction.

• Cyanoethylation of amines.[5][6]
• Cyanoethylation of phosphines.[7]
• Cyanoethylation of carbon nucleophiles.[8] In one commercial example, acetone is cyanoethylated to give the keto hexanenitrile, a precursor to 2-methylpyridine.[9]

An alternative method for cyanoethylation entails alkylation of the substrate with 3-chloropropionitrile.