SolutionsPreparation
1. Choose the method
How would you prepare: a) pentanenitrile from 1-bromobutane; b) benzonitrile from aniline; c) 2-hydroxy-2-methylpropanenitrile from acetone?
- NaCN in DMSO (SN2).
- NaNO2/HCl at 0 °C, then CuCN (Sandmeyer reaction).
- HCN (or NaCN and acid): the cyanohydrin forms.
2. Substitution or elimination
Why is 2,2-dimethylpropanenitrile not prepared from 2-bromo-2-methylpropane and NaCN?
A tertiary halide does not undergo SN2; with cyanide, which is also basic, elimination predominates and methylpropene is obtained.