Question

Tischenko reaction is a modification of:
A. Aldol condensation
B. Claisen condensation
C. Cannizzaro reaction
D. Pinacol- pinacolone reaction

Answer 1

The Tishchenko reaction is an organic chemical reaction that involves disproportionation of an aldehyde in the presence of an alkoxide. The reaction is named after Russian organic chemist Vyacheslav Tishchenko, who discovered that aluminium alkoxides are effective catalysts for the reaction.

Complete answer:
The Tischenko reaction is a modification of the Cannizzaro reaction. The Tishchenko reaction is an organic chemical reaction that involves disproportionation of an aldehyde lacking a hydrogen atom in the alpha position in the presence of an alkoxide. The Tishchenko Reaction is a disproportionation reaction that allows the preparation of esters from two equivalents of an aldehyde.
The Cannizzaro reaction, named after its discoverer Stanislao Cannizzaro, is a chemical reaction that involves the base-induced disproportionation of two molecules of a non-enolizable aldehyde to give a primary alcohol and a carboxylic acid.
The reaction product of the Tischenko reaction is an ester. The reaction mechanism of the Tischenko reaction is as follows:

The reaction mechanism of the Cannizzaro reaction can be shown as follows:

In the Cannizzaro reaction, two molecules of aldehyde react with each other in the presence of a strong base to give an ester which, on hydrolysis, gives a carboxylic acid and an alcohol as the product.

Thus, the correct option is C. Cannizzaro reaction.

Note:
The product of the Tishchenko reaction is an ester and is derived from the Cannizzaro reaction as in the later; the intermediate product is the final product of the Tischenko reaction (ester). The only difference in both the reactions is the reagent that has been used in both the reactions.