14.28:

Nitriles to Amines: LiAlH4 Reduction

JoVE Core
Organic Chemistry
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JoVE Core Organic Chemistry
Nitriles to Amines: LiAlH4 Reduction

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00:55 min

April 30, 2023

Nitriles are reduced to amines in the presence of strong reducing agents like lithium aluminum hydride through a typical nucleophilic acyl substitution. The reaction requires two equivalents of the reducing agent. The reducing agent acts as a source of hydride ions.

As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to generate a dianion. A final protonation of the dianion with water yields a primary amine as the final product.

Figure1

A milder reducing agent like diisobutylaluminum hydride reduces nitriles to aldehydes. In this reaction, nitrile reacts with one equivalent of the reducing agent. This is followed by hydrolysis to yield aldehyde.