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An organolithium reagent or Grignard reagent attacks a nitrile to form the magnesium salt of an imine. The final product ( a ketone) is formed by the acidic hydrolysis of the imine. This mechanism is just the opposite of acid-catalyzed imine formation. In another process, a nitrile can undergo reduction with DIBAL-H to form an aluminum complex which on hydrolysis gives the aldehyde.

The starting material used for the synthesis of a ketone can be a nitrile. The compounds containing the cyano (-C鈮�N) functional group are known as nitrile. Since nitrogen is more electronegative than carbon, the -C鈮�N is more polarized such as the C=O bond of the carbonyl group. Nucleophiles can be added to -C鈮�N just by attacking the electrophilic carbon atom. Magnesium salt of an imine is formed by the attack of Grignard or organolithium reagent to nitriles which undergoes acidic hydrolysis to form the desired ketone.

(a) Bromo benzene on treatment with forms phenyl magnesium bromide. Phenyl magnesium bromide on further treatment with propionitrile followed by acidic hydrolysis forms the desired product propiophenone.

(b) Propionitrile on treatment with butyl magnesium bromide ( grignard reagent) forms a magnesium salt of an imine which on acidic hydrolysis gives the desired product as heptan-3-one.

(c) Benzoic acid on treatment with cyclopentyl lithium (organolithium reagent ) forms a dianion which on acidic hydrolysis followed by a loss of water molecule forms the desired product as phenyl cyclopently ketone.

(d) 1-bromo-hept-2-ene on treatment with NaCl forms a nitrile which on further treatment with DIBAL-H followed by acidic hydrolysis forms the desired product as oct-3-enal.