Chemical Sciences: A Manual for CSIR-UGC National Eligibility Test for Lectureship and JRF/Named Reactions/Reimer-Tiemann Reaction

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The Reimer-Tiemann reaction is a chemical reaction used for the ortho-formylation of phenols. The reaction was discovered by Karl Ludwig Reimer and Ferdinand Tiemann. In the simplest case, the product is salicylaldehyde:

The Reimer-Tiemann reaction

Reaction mechanism[edit]

Chloroform (1) reacts with strong base to form the chloroform carbanion (2), which will quickly alpha-eliminate to give dichlorocarbene (3). Dichlorocarbene will react in the ortho- and para- position of the phenate (5) to give the dichloromethyl substituted phenol (7). After basic hydrolysis, the desired product (9) is formed.

The mechanism of the Reimer-Tiemann reaction