In the experiment Thiamine Catalyzed Benzoin Condensation Wh

In the experiment \"Thiamine Catalyzed Benzoin Condensation\" What is the importance of thiamine hydrochloride in this reaction? Describe the characteristics which make it an ideal catalyst for this reaction.

Solution

a) Thiamine hydrochloride acts as a catalyst in the benzoin condensation reaction. It only facilitates the formation of the benzoin from the benzaldehyde and did not get consumed in the reaction as it is regenerated at the completion of the reaction.  

b) The characteristics which make it an ideal catalyst for this reaction are given below:

i) Thiamine hydrochloride is a good leaving group.

ii) It is also a good nucleophile where it forms a high concentration of its ylide in the presence of a base.

iii) The intermediate anion is stabilized in the presence of this catalyst.