Nitrile reduction
Abstract
Nitrile reduction consists in the conversion of a nitrile (R–C≡N) into a primary amine by formal addition of two equivalents of H2 across the C≡N triple bond. It is one of the most direct and atom-efficient routes to primary amines in organic synthesis.
Keywords
Nitrile, Reduction, Primary amine
Category
Nitrile
Mechanism
First, a hydride ion (H-) from LiAlH4 attacks the electrophilic carbon of the nitrile group, forming a lithium complex. The nitrogen atom coordinates to the aluminum center, activating the intermediate toward further reduction. A second hydride then attacks the electrophilic carbon of the imine, giving an aluminum-coordinated amide anion. The nitrogen remains coordinated to aluminum throughout. Finally, hydrolysis of the aluminum–nitrogen complex with H2O followed by aqueous NaOH (or workup with NH4Cl) releases the primary amine along with aluminium hydroxide as by-product.
