Stephen reaction
A nitrile is reduced by stannous chloride in HCl to an imine salt, which hydrolyses to an aldehyde.
EthanenitrileCH₃CNNitrile - Step 1
(i) SnCl₂ + HCl (ii) H₃O⁺
EthanalCH₃CHOAldehyde
How it works
- SnCl₂ and HCl reduce the C triple-bond N group to an imine hydrochloride (RCH=NH.HCl).
- Hydrolysis with H₃O⁺ converts the imine to the aldehyde.
- NH₄Cl is the by-product.
What it makes
Aldehydes with the same carbon count as the nitrile.
Where it fails
It stops at the aldehyde and does not give ketones.
Class 12, Chapter 8 Aldehydes, Ketones and Carboxylic Acids
Stephen reaction: quick answers
What is the intermediate?
An imine hydrochloride.
Does the Stephen reaction change the carbon count?
No, the aldehyde has the same carbons as the nitrile.
What else reduces a nitrile to an aldehyde?
DIBAL-H followed by water.