Haloform Reaction

This reaction has been used in qualitative analysis to indicate the presence of a methyl ketone. The product iodoform is yellow and has a characteristic odour. The reaction has some synthetic utility in the oxidative demethylation of methyl ketones if the other substituent on the carbonyl groups bears no enolizable α-protons.

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Mechanism

The reaction readily proceeds to completion because of the acidifying effect of the halogen substituents.