Reimer tiemann Reaction

This involves the treatment of phenol with chloroform in aqueous sodium hydroxide solution followed by acid hydrolysis salicylaldehyde is formed if carbon tetra chloride is used in place of chloroform salicylic acid is formed.

The reimer-Tiemann reaction is also give by other phenols and introduces -CHO group in the ortho position.

Mechanism :

In the above reaction chloroform first reacts with sodium hydroxide to produce dichlorocarbene.

The electron deficient dichlorocarbene then reacts with sodium phenoxide to form a dihalide this is then hydrolysed to form the aldehyde.

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