The Ritter reaction is a chemical reaction that transforms a nitrile into an N-alkyl amide using various electrophilic alkylating reagents. The original reaction formed the alkylating agent using an alkene in the presence of a strong acid.

The Ritter reaction proceeds by the electrophilic addition of either a carbenium ion or covalent species to the nitrile. The resulting nitrilium ion is hydrolyzed to the desired amide.