Aldehydes, without alpha hydrogens, give the Cannizzaro reaction on treatment with a strong base (NaOH)


In this reaction one molecule is reduced to alcohol, while the other is oxidized to carboxylic acid.



Stage 1. Addition of the hydroxide ion to the carbonyl

cannizzaro mechanism 01


Stage 2. Hydride transfer

cannizzaro mechanism 02


Stage 3. Acid-base balance

cannizzaro mechanism 03