Reimer Tiemann reaction | Organic Reaction Mechanism
This is one of the very very important naming reactions in organic chemistry especially for students pursuing Higher Secondary and Bachelor’s Degree in Chemistry subjects.
This reaction is about Ortho-Formylation in aromatic alcohols.
Simply we can say, Reimer Tiemann Reaction
is used in the conversation of Phenol
This reaction is important because it contains the most important Reaction intermediate. That is Carbene.
Reimer Tiemann Reaction :-
When the Phenol and Chloroform are reacted in presence of a strong base like Potassium Hydroxide is forms Salicylaldehyde.
The general reaction is given below in the image
Formation of Carbene:-
First of all, the carbene
is formed by the reaction of KOH
( Potassium Hydroxide ) with Chloroform, it
forms trichloromethyl carbanion.
|Chloroform reacting With KOH
Then the formed trichloromethyl carbanion will be Converted into Carbene ( dichloromethylene )
Formation of Phenoxide ion:-
is reacted with KOH
and the base will obstruct the proton from the Phenol and it ends up in the formation of a Phenoxide ion.
|Convertion of Phenol to Phenoxide ion
The reaction of Carbene and Phenoxide ion:-
In this part, Phenoxide ion is reacted with Carbene intermediate in presence of KOH (Strong base).
Finally, it forms Salicylaldehyde.
|Reaction between Carbene & Phenoxide ion
|KCl – Elimination
After Adding the KOH base in the above process, KCl (Potassium Chloride) will eliminate. It forms -OH in the respective chain.
In this above step,
The proton transfer takes place. That is Proton of one Alcohol group is shifted to another group.
So Conversion of Phenol ( any aromatic alcohol ) into Salicylaldehyde is known as Reimer Tiemann Reaction.
Key Notes :-
• This reaction is also get done in Aromatic alcohols with Heteroatom’s like Thiolate etc..,
• The intermediate formed in this reaction is a very short-living Species called Carbene
• The temperature of the reaction is carried out in 60°C.
• It is position specific reaction ( Ortho – Formylation )
• The IUPAC name of the product formed in this reaction is 2-hydroxy Benzaldehyde.
Frequently Asked Questions:-
Here i give 5 frequently asked questions in this above reaction. Try to answer it.
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