Reimer-Tiemann reaction

Schematic of the Reimer-Tiemann reaction. Reagents: phenol, chloroform (CHCl3), base, acid work-up. Product: o-hydroxy benzaldehyde.

The Reimer-Tiemann reaction is an organic reaction used to convert a phenol to an o-hydroxy benzalde-hyde using chloroform, a base, and acid work-up. The mechanism begins with abstraction of the proton from chloroform with the base to form a trichlorocarbanion which spontaneously loses a chloride ion to form a neutral dichlorocarbene. The base also deprotonates the phenol reagent which then attacks the carbene. A series of steps and a final acid work-up result in the o-hydroxy benzaldehyde product.[1][2][3]

Mechanism

Mechanism of the Reimer-Tiemann reaction.

References:

1.
Reimer, K. Ber. Dtsch. Chem. Ges. 1876, 9, 423–424.
2.
Reimer, K.; Tiemann, F. Ber. Dtsch. Chem. Ges. 1876, 9, 824–828.
3.
Reimer, K.; Tiemann, F. Ber. Dtsch. Chem. Ges. 1876, 9, 1268–1278.

Other Formylation Reactions: