Nucleophilic substitution — cyanide ions

Year 1

AQA 3.3.3

Nucleophilic substitution & elimination · KCN in aqueous ethanol · warm

Reagents: KCN in aqueous ethanol · Conditions: warm

Step 1 of 1

1.The lone pair on the CARBON of CN⁻ attacks the δ+ carbon (attack through C, not N — that's how the new C–C bond forms).
2.The C–Br bond breaks heterolytically towards bromine.

CN⁻ bonds to carbon as Br⁻ leaves: propanenitrile (chain extended by one carbon).

Product: propanenitrile

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