Reimer‐Tiemann Reaction

The transformation of a formyl group onto the ortho ‐ or para ‐position of an activating group in an electron‐rich aromatic compound by warming with chloroform and aqueous alkali is generally known as the Reimer–Tiemann reaction. Several electron‐rich aromatic compounds have been suggested for this reaction. This reaction also possesses various drawbacks and the presence of an alcohol may alter the nature of the biphasic system. It has been found that this reaction generally favors the ortho ‐formylated product because of the electrostatic effect. This reaction has been improved by use of a slightly hydrated solid‐liquid medium. This reaction has been applied for the formylation of electron‐rich aromatic compounds.