Explain Duff reaction
The Duff reaction or hexamine aromatic formylation is a formylation reaction used in organic chemistry for the synthesis of benzaldehydes with hexamine as the formyl carbon source.[1][2][3][4][5][6] It is named after James Cooper Duff, who was a chemist at the College of Technology, Birmingham, around 1920–1950.
The electrophilic species in this electrophilic aromatic substitution reaction is the iminium ion CH2+NR2. The initial reaction product is an iminium which is hydrolyzed to the aldehyde. See mechanism below. The reaction requires strongly electron donating substituents on the aromatic ring such as in a phenol. Formylation occurs ortho to the electron donating substituent preferentially, unless the ortho positins are blocked, in which case the formylation occurs para.[7]