Question

Reaction of isocyanide with LiALH4

Answer 1

Secondary amine ($R-NH-CH_3$)

Answer 2

Isocyanides ($R-N \equiv C$) are reduced by lithium aluminum hydride ($LiAlH_4$) to secondary amines ($R-NH-CH_3$). The reaction involves the addition of two hydride equivalents across the $N \equiv C$ triple bond. The mechanism typically involves coordination of LiAlH4 to the nitrogen atom, making the carbon atom electrophilic, followed by nucleophilic attack of hydride ($H^-$) on the carbon. This is followed by a second hydride addition and subsequent hydrolysis to yield the secondary amine.

The general structure of an isocyanide is $R-N \equiv C$, where $R$ is an alkyl or aryl group. The carbon atom is bonded to nitrogen via a triple bond.

The overall reaction of an isocyanide with $LiAlH_4$ followed by hydrolysis ($H_2O$) yields a secondary amine.

$$R-N \equiv C \xrightarrow{LiAlH_4, H_2O} R-NH-CH_3$$

Smiles Representation:

• Isocyanide: R-N#C
• Secondary Amine Product: R-N(C)H (Here, the C represents the methyl carbon atom, and the implicit bond to H on nitrogen is shown by H after N(C))