Give the conversion of phenol to salicylaldehyde.

(N/A) The conversion of phenol to salicylaldehyde is achieved through the $Reimer-Tiemann$ reaction.
When phenol is treated with chloroform $(CHCl_3)$ in the presence of aqueous sodium hydroxide $(NaOH)$ at $340 \ K$,an aldehyde group $(-CHO)$ is introduced at the ortho position of the phenol.
This reaction proceeds via the formation of a dichlorocarbene intermediate,which attacks the phenoxide ion.
The resulting intermediate is a substituted benzal chloride,which undergoes hydrolysis in the presence of alkali to yield salicylaldehyde $(2-hydroxybenzaldehyde)$.