Duff reaction

The Duff reaction is a name reaction in organic chemistry and named after James Cooper Duff. The reaction is used to introduce a formyl group ( -CHO) in aromatic hydrocarbons. Hexamethylenetetramine is used in this reaction as the source of the introduced carbonyl group. Is favored by the reaction of activated aromatic compounds such as phenol.

Mechanism

In the first step 1 of hexamethylenetetramine is protonated. This produces a iminium 2 which engages in the aromatic electrophilic substitution reaction. In further reaction steps, the compound 8 is produced is then hydrolyzed. After further rearrangements of the desired formylated aromatic created 11

Examples

Formylation occurs at the ortho position to the electron-donating substituents are preferred. Is the ortho- position reception, the formylation occurs at the para position. An example is the synthesis of 3,5-di- tert- butylsalicylaldehyde:

And the synthesis of syringaldehyde: