Organometallic reagents reaction with nitriles

Reaction of Nitriles with Organometallic Reagents Grignard reagents add to a nitrile to give an intermediate imine anion that is hydrolyzed by addition of water to yield a ketone. 

Nitriles are similar in some respects to carboxylic acids and are prepared either by SN2 reaction of an alkyl halide with cyanide ion or by dehydration of an amide. Nitriles undergo nucleophilic addition to the polar C=N bond in the same way that carbonyl compounds do. The most important reactions of nitriles are their hydrolysis to carboxylic acids, reduction to primary amines, and reaction with organometallic reagents to yield ketones. 

Monoalkylation of primary amines. A two-step sequence for this reaction involves conversion of the amine to the N-(cyanomethyl)amine (2) by reaction with chloroaceto-nitrile or with formaldehyde and KCN. Reaction of 2 with an organolithium or a Grignard reagent generates an unstable formaldehyde imint (a) that reacts with a second equivalent of the organometallic reagent to form a secondary amine (3). 

The aryl unit of these species shows carbanionic properties and consequently reacts with electrophiles. As a result, these organometallic reagents are of great value for the synthesis of a wide range of aromatic compounds. In particular, reaction with carbon electrophiles such as carbonyl compounds and nitriles results in the formation of a new carbon-carbon bond. 

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