The Reimer-Tiemann reaction involves treating phenol with chloroform in the presence of sodium hydroxide, resulting in the introduction of a -CHO group at the ortho position of the benzene ring. The intermediate benzal chloride is hydrolyzed to produce salicylaldehyde.
Describe the Reimer-Tiemann reaction and the role of chloroform and sodium hydroxide in introducing a -CHO group to the ortho position of the benzene ring in phenol.
Share
The Reimer-Tiemann reaction involves introducing a formyl group (-CHO) to the ortho position of a phenol ring. Chloroform (CHCl₃) reacts with sodium hydroxide (NaOH) to form the chloroform anion (CHCl₂⁻) and sodium chloride (NaCl). The chloroform anion then undergoes nucleophilic attack by phenolate ion (generated from phenol by NaOH), leading to the formation of a carbene intermediate. This intermediate subsequently undergoes rearrangement and reaction with phenol, resulting in the substitution of an -CHO group at the ortho position. The Reimer-Tiemann reaction is a method for the synthesis of salicylaldehyde from phenol.